UNIVERSITY  OF  ILLINOIS 

CHEMISTRY  DEPARTMENT 

ARTHUR  WILLIAM  PALMER 
MEMORIAL  LIBRARY 
1904 


5V\ 
ft*  5 


Return  this  book  on  or  before  the 
Latest  Date  stamped  below.  A 
charge  is  made  on  all  overdue 
books. 

University  of  Illinois  Library 


Digitized  by  the  Internet  Archive 
in  2017  with  funding  from 

University  of  Illinois  Urbana-Champaign  Alternates 


https://archive.org/details/chaptersoncarbonOOappl 


CHAPTERS 


ON  THE 

CARBON  COMPOUNDS: 

AN 

ELEMENTARY  TEXT-BOOK 


OF 

Organic  Chemistry, 


JOHN  HOWARD  APPLETON,  A.  M. 


Professor  of  Chemistry  in  Brown  University. 


AUTHOR  OF  A SERIES  OF  CHEMICAL  TEXT-BOOKS. 


SECOND  EDITION. 


PROVIDENCE  : 

Snow  & Farnham,  Printers, 
1896. 


PROFESSOR  APPLETON’S  CHEMICAL  TEXT  BOOKS. 


The  Beginner’s  Handbook  of  Chemistry.  The  Non-Metals.  This  is  an  introduc- 
tion to  the  study  of  Chemistry,  suitable  for  general  readers.  It  treats  chiefly  the  non-metals,  these 
being  generally  found  to  furnish  the  best  material  for  an  elementary  course,  and  to  illustrate  best 
the  fundamental  facts  and  principles  of  the  science. 

The  Metals  of  the  Chemist.  This  is  an  elementary  text-book  for  schools  and  colleges. 
It  deals  with  all  the  recognized  metals  and  with  many  of  the  most  important  applications  of  them. 

The  Carbon  Compounds.  An  elementary  organic  chemistry.  This  book  with  the  two 
preceding,  is  intended  to  complete  a brief  course  covering  the  entire  field  of  general  chemistry. 


The  Young  Chemist.  A book  of  chemical  experiments  for  beginners  in  chemistry.  This 
is  designed  for  use  in  schools  and  colleges.  It  is  composed  almost  entirely  of  experiments,  those 
being  chosen  that  may  be  performed  with  very  simple  apparatus.  The  book  is  arranged  in  a 
clear,  systematic,  and  instructive  manner. 

Qualitative  Analysis.  A brief  but  thorough  manual  for  laboratory  use. 

It  gives  full  explanations  and  many  chemical  equations.  The  processes  of  analysis  are 
clearly  stated,  and  the  whole  subject  is  handled  in  a manner  that  has  been  highly  commended  by 
a multitude  of  successful  teachers  of  this  branch. 

Quantitative  Analysis.  A text-book  for  school  and  college  laboratories. 

This  volume  possesses  novel  and  striking  merits,  such  as  will  make  it  worthy  of  the  same 
decided  approbation  and  large  sale  that  have  been  awarded  to  the  earlier  books  of  this  series. 
The  treatment  of  the  subject  is  such  that  the  pupil  gains  an  acquaintance  with  the  best  methods  of 
determining  all  the  principal  elements,  as  well  as  •with  the  most  important  type-processes  both  of 
gravimetric  and  volumetric  analysis. 


First  Report-book;  for  Chemical  Experiments.  A well  arranged  memorandum 
book,  with  blank  spaces  to  be  filled  by  the  pupil  during  the  progress  of  his  experiments. 

The  making  of  a succinct  report  by  the  student  is  of  great  service  in  leading  him  to  form  the 
habit  of  taking  written  notes  while  the  facts  of  the  experiment  are  fresh  in  the  mind.  Moreover, 
it  undoubtedly  increases  the  powers  of  observation. 

This  Report-book  is  so  constructed  that  it  may  be  used  with  “ The  Young  Chemist”  or  with 
any  text-book  on  general  chemistry. 

Second  Report-book  ; for  Qualitative  Analysis.  It  is  so  arranged  that  it  may  be  used 
with  Appleton’s  Qualitative  Analysis. 

Third  Report-book  ; for  Quantitative  Analysis.  It  is  so  arranged  that  a student  may 
preserve  a statement  of  his  work  in  this  branch.  Spaces  are  provided  for  the  record  of  the 
weights  of  crucibles,  etc.,  and  a blank  page  is  afforded  for  the  computations  necessary  in  each 
case. 


Chemical  Philosophy.  This  book  deals  with  certain  general  principles  of  chemical  sci- 
ence, such  as  the  constitution  of  matter;  atoms,  molecules,  and  masses;  the  three  states  of 
matter  and  radiant  matter;  the  change  of  state  from  one  form  of  matter  to  another.  It  also 
presents  such  topics  as  Boyle’s  and  Mariotte’s  law,  Charles’  law,  and  the  other  general  laws  of 
matter.  It  discusses  from  a chemical  standpoint  certain  forms  of  energy,  such  as  heat,  light, 
electricity.  It  treats  of  the  nature  of  chemical  affinity;  the  chemical  work  of  micro-organisms; 
the  modes  of  chemical  action;  thermo-chemistry;  and  those  attractions  of  substances  which  are 
partly  physical  and  partly  chemical.  It  also  presents  a full  study  of  atomic  weights ; the  methods 
leading  to  a first  adoption  of  them,  and  then  to  the  grounds  sustaining  certain  numbers  selected. 
The  periodic  system  is  of  course  discussed. 


Copyright,  iSq6,  by  John  Howard  Appleton. 


PREFACE. 


This  little  volume  is  the  third  and  last  of  a series  of 
text-books  on  general  or  descriptive  chemistry,  prepared  for 
the  use  of  beginners.  The  first  of  the  series  treats  chiefly 
of  non-metals;  the  second  treats  of  the  metals  of  the  chem- 
ist  ; and  this  one,  of  carbon  compounds. 

The  carbon  compounds  are  so  numerous,  and  in  some  cases, 
so  complicated  in  their  structure,  that  it  is  impossible  to 
deal  with  more  than  a very  small  portion  of  them  in  the  few 
pages  allotted  to  this  book.  It  is  hoped,  however,  that  the 
following  pages  may  serve  as  a tolerable  introduction  to  the 
wonderful  and  fascinating  branch  to  which  it  relates. 

The  book  is  not  intended  to  be  used  alone;  it  is  expected 
that  the  student  will  do  laboratory  work  in  connection  with  it. 
While  many  of  the  experiments  in  organic  chemistry  require 
complicated  apparatus  and  considerable  manipulative  skill, 
there  are  others  that  may  be  performed  on  a small  scale  and 
with  simple  appliances,  by  students  of  limited  experience. 
Such  experiments,  properly  ordered,  will  serve  to  illustrate  the 
facts  and  principles  presented  in  a text-book  like  the  present 
one,  and  will  add  greatly  to  the  interest  and  satisfaction  of 
pupils  studying  it. 

In  preparing  this  edition  the  matter  of  the  first  edition 
has  been  completely  rearranged  and  largely  rewritten ; more- 
over, very  considerable  additions  have  been  made. 

Brown  University,  Providence,  R.  I., 

January,  1896. 


64647 


CONTENTS, 


CHAPTER  I. — Organic  and  inorganic  chemistry ...  i 

CHAPTER  II. — The  study  of  organic  compounds.  Ultimate  analysis  and 

proximate  analysis io 

CHAPTER  III. — Proximate  metamorphosis  of  organic  bodies  : the  sub- 
ject considered  primarily  with  reference  to  the  operations  performed.  14 
CHAPTER  IV. — Proximate  metamorphosis  of  organic  compounds:  the 

subject  considered  with  reference  to  the  products  obtained 22 

CHAPTER  V. — Binary  carbon  compounds.  Compounds  containing 

hydrogen,  or  chlorine,  or  oxygen,  or  sulphur,  or  nitrogen 27 

CHAPTER  VI. — Hydrocarbons:  fatty  series  and  aromatic  series 34 

CHAPTER  VII. — Fatty  hydrocarbons:  paraffin  series;  olefine  series; 

acetylene  series  ; valylene  series ; diacetylene  series 38 

CHAPTER  VIII. — Petroleum,  natural  gas,  asphaltum,  ozocerite 48 

CHAPTER  IX. — Halogen  derivatives  of  fatty  hydrocarbons 62 

CHAPTER  X. — Alcohols  of  the  fatty  series 64 

CHAPTER  XI. — Ethers  and  esters,  etc 76 

CHAPTER  XII. — Organic  acids,  fatty  series 80 

CHAPTER  XIII. — Aldehydes  and  ketones 102 

CHAPTER  XIV. — Carbohydrates;  especially  sugars 105 

CHAPTER  XV. — Carbohydrates;  starch 119 

CHAPTER  XVI. — Carbohydrates;  cellulose  (paper,  textiles,)  gums,  glu- 

cosides 122 

CHAPTER  XVII. — Fatty  compounds  containing  nitrogen  and  similar 

non-metals 131 

CHAPTER  XVIII. — Certain  organic  compounds  containing  metallic  ele- 
ments  135 

CHAPTER  XIX. — Aromatic  compounds.  General  statements 136 

CHAPTER  XX. — Hydrocarbons  of  the  aromatic  series 145 

CHAPTER  XXI. — Certain  special  aromatic  hydrocarbons 15 1 

CHAPTER  XXII. — Aromatic  substitution  compounds,  etc 158 

CHAPTER  XXIII. — Certain  natural  organic  coloring  matters,  etc 177 

Alkaloids 180 


CARBON  COMPOUNDS. 


CHAPTER  I. 


ORGANIC  AND  INORGANIC  CHEMISTRY. 

Chemists  long  ago  recognized  certain  differences  between  the 
substances  found  in  distinctly  animal  and  vegetable  matters,  on 
the  one  hand,  and  the  substances  found  in  mineral  matters,  on  the 
other  : between  those  things  which  constitute  organisms  like  ani- 
mals and  plants,  as  compared  with  those  of  non-living  substances 
like  clay,  iron-rust,  alum,  saltpetre,  etc. 

Animal  matters  and  vegetable  matters  are  the  products  of 
bodies  possessing  organs.  Organs  are  parts  having  specific  func- 
tions. Thus  the  stomach  is  an  organ  possessing  the  function  of 
digestion,  and  the  lungs  are  organs  possessing  the  function  of 
respiration.  Again,  the  leaves,  the  flowers,  the  seeds,  the  roots, 
of  plants,  are  separate  organs,  or  possess  separate  organs,  and 
they  perform  special  and  very  different  functions  of  the  living 
vegetable  to  which  they  belong.  Accordingly,  substances  derived 
from  vegetables  and  animals  are  called  organic . Non-living  obj  ects, 
as  rocks  and  other  mineral  and  earthy  substances  do  not  possess 
organs,  and  they  have  long  been  called  inorganic. 

This  division  of  matters  into  organic  and  inorganic  was  formerly  thought  an 
essential  one;  it  is  not  now  considered  so.  It  is  now  known  that  the  chemical 
changes  of  living  animals  and  plants  are  governed  by  the  same  laws  as  those 
prevailing  in  the  changes  of  rocks  and  other  lifeless  forms  of  matter. 

Grounds  for  Dividing  Chemistry  into  Two  Great 
Departments. 

Chemistry  is  still,  however,  commonly  divided  into  the  two 
great  departments — inorganic  chemistry  and  organic  chemistry  ; 
but  this  division  is  recognized  as  a matter  of  convenience  mainly. 

Three  reasons  may  be  mentioned,  why  the  distinction  is  still 
maintained : 

First . The  number  of  organic  compounds  is  very  great. 

Second.  These  compounds  perform  varied  and  important  offices  in  connec- 

(0 


2 


CARBON  COMPOUNDS. 


tion  with  human  beings  in  their  growth  and  nourishment  in  health,  and  in  their 
treatment  in  illness.  Many  organic  compounds  have  important  applications  in 
the  arts. 

Third.  As  will  appear  hereafter,  the  processes  of  analysis,  and  methods  of 
investigation  in  organic  compounds  are  slightly  different,  as  a whole,  from 
those  that  serve  for  the  study  of  inorganic. 

Definitions  of  Organic  Chemistry, 

The  inorganic  and  the  organic  worlds  are,  however,  so  closely 
allied  in  some  respects,  and  certain  of  the  substances  of  the  one 
have  such  close  and  natural  affiliations  with  those  of  the  other, 
that  it  is  often  found  difficult  to  determine  where  shall  be  placed 
the  line  of  demarcation  between  these  two  great  natural  groups. 
In  fact,  chemists  have  not  found  the  definition,  incidentally  intro- 
duced in  the  preceding  paragraph,  sufficiently  distinct.  To  make 
it  more  so,  organic  chemistry  has  been  sometimes  called  the 
chemistry  of  the  carbon  compounds . It  has  sometimes  been  called 
the  chemistry  of  the  hydrocarbons.  Again,  the  following  still  more 
rigid  and  scientific  statement  is  often  employed  : organic  chemis- 
try includes  those  compounds  in  which  the  atoms  of  carbon  are 
directly  united  either  with  other  atoms  of  carbon , or  with  atoms  of 
hydrogen , or  with  atoms  of  nitrogen. 

The  last  three  definitions  exclude  from  organic  chemistry  such 
animal  substances  as  bone  (principally  calcium  phosphate)  and 
the  last  two  definitions  exclude  such  substances  as  carbon  dioxide, 
C02,  and  carbon  disulphide,  CS2. 

Two  Classes  of  Organic  Compounds. 

There  is  one  distinction  between  the  classes  of  organic  com- 
pounds that  ought  not  to  be  omitted  here.  The  members  of  the 
organic  family  differ  very  much  in  their  properties,  according  as 
they  are  crystalline  or  cellular.  Crystalline  organic  compounds, 
of  which  cane  sugar  may  be  taken  as  a familiar  and  suitable  exam- 
ple, are  numerous.  These  compounds  are  closely  allied  in  some 
respects  to  inorganic  compounds.  They  do  not  seem  to  have  so 
close  a relation  to  the  vital  processes  as  might  at  first  be  expected. 
But  those  organic  compounds  that  are  cellular,  such,  for  example, 
as  the  fibre  of  wood  and  the  fibre  of  lean  meat,  are  much  removed 
from  inorganic  bodies,  and  seem  to  bear  a peculiar  and  close  rela- 
tion to  the  vital  forces. 


ORGANIC  AND  INORGANIC  COMPOUNDS . 


3 


Cellular  organic  compounds  are  often  called  organized ; crystal- 
lie  organic  compounds  are  often  called  unorganized. 

It  is  worth  while  to  note  that  certain  mineral  matters  contain  organic  com- 
pounds. Coal  is  a mixture  of  organic  substances ; so  is  petroleum. 


The  Great  Number  of  Organic  Compounds. 

The  vast  number  of  organic  compounds  is  referable  to  at  least 
four  fundamental  principles  : 

First.  The  chief  element,  carbon,  has  a large  number  of  points 
of  attraction  — that  is,  four;  on  this  account  it  is  capable  of 
attaching  to  itself  by  chemical  affinity  many  other  atoms. 

Second.  Carbon  atoms  are  capable  of  uniting  in  chains  of 
great  length  and  variety  of  arrangement.  Two  methods  of 
arrangement  are  especially  noteworthy ; the  one  method  is  that 
where  the  chains  are  open  — that  is,  not  attached  at  the  ends. 
The  other  arrangement  is  that  where  the  chains  are  closed , the 
series  of  atoms  of  carbon  making  a sort  of  ring.  An  appropriate 
example  of  this  kind  of  union  is  found  in  the  benzene  ring  or 
benzene  hexagon. 

The  open  chain  may  be  conveniently  represented  by  the  left- 
hand  diagram  below,  and  the  closed  chain,  the  benzene  ring,  is 
often  represented  by  the  right-hand  diagram  below. 


H 

H 

1 

C 

H— C— H 

//  \ 

| 

H— C ( 

H— C— H 
| 

1 

H— C < 

H— C— H 

^ / 

| 

C 

H 

1 

C— II 
II 

C— H 


H 


The  exact  nature  of  carbon  atoms  by  reason  of  which  they  form  such  chains 
is  not  known.  It  is  worthy  of  note  that  thus  far  only  two  compounds  of  carbon 
with  oxygen  are  known,  carbon  monoxide,  CO,  and  carbon  dioxide,  C02. 
With  hydrogen  alone,  on  the  other  hand,  carbon  forms  hundreds  of  known 
compounds.  Undoubtedly  some  good  reason  exists  for  this  great  disparity,  but 
it  is  as  yet  undetected. 

Third.  One  of  the  most  interesting  and  important  features  of 
organic  compounds  is  that  in  them  certain  elements  may  stay 
together  with  considerable  stability  in  comparatively  permanent 


4 


CARBON  COMPOUNDS. 


groups  which  act  like  elements.  Such  groups  of  atoms  are 
called  compound  radicles. 

It  has  already  been  shown  that  the  number  of  elements  is 
about  seventy,  and  that  these  elements  uniting  in  a variety  of 
ways  form  a vast  number  of  compounds.  The  organic  chemist 
has  to  do  not  only  with  the  seventy  well  known  elements  but 
with  a vast  number  of  radicles  which  act  like  elements.  These 
radicles,  therefore,  add  very  greatly  to  the  capabilities  of  organic 
chemistry. 

It  is  not  practicable  to  attempt  here  a list  of  the  radicles  of  organic  chemistry. 
‘Many  of  them  will  appear  in  subsequent  pages  and  be  readily  recognized  as 
maintaining  such  integrity  through  a series  of  chemical  operations  as  to  entitle 
them  to  rank  as  units  comparable  to  the  atoms  of  the  metals  and  non-metals. 
A few  very  common  ones  may  be  mentioned  : 

Methyl,  CH3 
Ethyl,  C2H5 
Propyl,  C3H7 
Phenyl,  CeH5 
Cyanogen,  CN 


A few  inorganic  radicles  are  of  great  importance  in  organic  transforma- 
tions, as, 

Hydroxyl,  IIO 

Carbonyl,  CO 

Carboxyl,  COOH 

The  nitro  group,  N02 

The  nitroso  group,  NO 

The  amido  group,  NH2 

The  imido  group,  NH 

The  sulpho  group,  S02 

The  thionyl  group,  SO 

The  sulphonating  group,  HS03 

Fourth.  It  is  now  distinctly  recognized  that  a given  organic 
compound,  possessing  a certain  distinct  set  of  properties,  may 
have  its  atoms  undergo  a rearrangement  without  any  increase  in 
the  number  of  them  or  any  change  in  their  kinds  or  relative  pro- 
portions. 

Some  organic  substances  have  molecules  capable  of  several  dif- 
ferent rearrangements,  such  that  several*  different  compounds 
may  be  produced.  Thus  Professor  Cayley  has  computed  that  a 
compound  of  the  paraffin  group  containing  four  carbon  atoms  is 


ORGANIC  AND  INORGANIC  COMPOUNDS. 


5 


capable  of  two  rearrangements  within  the  molecule ; but  a com- 
pound of  this  group  containing  thirteen  carbon  atoms  is  capable 
of  as  many  as  seven  hundred  and  ninety-nine  different  rearrange- 
ments of  its  atoms.*  This  property  of  organic  compounds  is 
called  isomerism. 

In  other  words,  two  or  more  substances  having  the  same  percent- 
age  of  carbon , hydrogen , and,  it  may  be,  of  other  elements,  may 
have  different  properties. 

There  are  several  different  kinds  of  isomerism  which  are 
worthy  of  explanation.  Such  are  true  isomerism,  polymerism, 
metamerism,  geometrical  isomerism,  etc. 

I.  Two  or  more  compounds  are  truly  isomeric  when  they  have  the  same 
elements  united  in  the  same  percentage  proportions  and  with  the  same  number 
of  atoms  in  the  molecule  — but  differ  in  the  arrangement  of  these  atoms.  The 
following  may  serve  as  examples  : 

Three  Strictly  Isomeric  Compounds. 

H 

HCH 

I 

HCH 

HCH 

I 

HCH 

I 

HCH 

H 

Normal  pentane. 

Two  Strictly  Isomeric  Compounds. 


Cl 

H 

H— C— H 

H— C— H 

H— C— H 

H— C— Cl 

Cl 

Cl 

Ethylene  chloride. 

Ethidene  chloride. 

II.  Two  or  more  compounds  are  metameric  when  they  possess  the  same  ele- 
mentary substances  united  with  the  same  percentage  composition  and  the  same 
molecular  weight  but  contain  different  evident  compound  radicles.  Metamer- 
ism is  exemplified  chiefly,  as  might  be  theoretically  expected,  in  ethers,  amines, 
and  esters. 


H 

HCH 

I H 

HC— CH 
I H 
HCH 

I 

HCH 

H 


Isopentane. 


H 

HCH 
H | H 

HC— C— CH 
H | H 

HCH 
H 


Mesopentane. 


* Cayley,  “ On  the  analytical  forms  called  trees,  with  applications,  the  theory  of  chemical  com- 
binations.” Brit.  Assoc.  Rep.  1875,  257.  Recalculated  by  Dr.  Hermann,  of  Wurtzburg. 
(Referred  to  in  Roscoe  & Schorlemmer’s  Chemistry,  vol.  iii.  Part  I.  p.  122.) 


6 


CARBON  COMPOUNDS. 


Three  Metameric  Compounds. 


1 

r c3h7 

! 

r ch3 

r ch3 

N 1 

H 

N ■ 

c2h5 

N \ CHg 

1 

l H 

H 

l ch3 

Propylamine. 

Methylethvlamine. 

Trimethylamine. 

III.  Two  or  more  compounds  are  polymeric  when  they  are  composed  of  the 
same  elementary  substances  with  the  same  percentage  composition,  but  have 
different  molecular  weights  and  different  number  of  atoms  in  the  molecule,  and 
of  course  different  formulas. 

Four  Polymeric  Compounds. 

Ethylene,  C2H4 
Propylene,  C3H6 
Butylene,  C4H8 
Amylene,  C5Hi0 

IV.  A fourth  kind  of  isomerism,  called  physical  isomerism,  geometrical  iso- 
merism, or  optical  isomerism,  has  of  late  come  to  be  widely  accepted.  It  is  a 
feature  of  what  is  called  stereo-chemistry;  a branch  developed  through  the 
studies  of  Le  Bel,  Van’t  Hoff  and  Wislicenus,  and  others.  In  this  view  two 
adjacent  carbon  atoms  are  viewed  as  having  their  points  of  attraction  distrib- 
uted in  space  as  if  at  the  four  apexes  of  a tetrahedron. 

When  such  a carbon  atom  has  its  four  points  of  attraction  satisfied  by  four 
different  atoms  or  radicles,  it  is  called  an  asymmetric  carbon  atom.  Evidently 
another  carbon  atom  may  have  the  same  four  radicles  arranged  in  a different 
order.  The  difference  between  the  two  arrangements  is  such  as  may  appear 
from  inspecting,  at  the  same  time,  a given  tetrahedron  and  its  image  reflected 
from  a mirror.  A compound  may  have  more  than  one  asymmetric  carbon 
atom. 

Lactic  acid,  C3H6O3  or  H3OCHOH-COOH,  has  one  asymmetric  carbon 
atom. 

It  has  been  shown  that  compounds  containing  one  or  more  asymmetric  car- 
bon atoms  have — when  liquified  or  in  solution  — certain  influence  on  the  ray  of 
light  passing  through  them. 

On  the  other  hand,  substances  possessing  such  optical  properties  are  usually 
assumed  to  have  asymmetric  carbon. 

V.  The  isomerism  characteristic  of  aromatic  compounds  is  discussed  later. 

Empirical  and  Rational  Formulas. 

In  an  empirical  formula,  the  atoms  are  arranged  in  some  order 
adopted,  but  all  atoms  of  a kind  are  put  together.  Thus,  the 
empirical  formula  of  trimethylamine  is  NC3H9. 

In  a rational  formula,  however,  the  atoms  are  arranged  in  an 
order  fixed  upon  after  a very  careful  study  of  the  compound. 
The  rational  formula  of  trimethylamine  is  N(CH3)3. 


ORGANIC  AND  INORGANIC  COMPOUNDS. 


7 


The  empirical  formula  of  ethyl  alcohol  is  C2H60.  The  rational 
formula  of  ethyl  alcohol  is  C2H5OH. 

Saturated  and  Unsaturated  Compounds. 

In  certain  carbon  compounds  each  of  the  four  points  of  every 
carbon  atom  is  attached  to  some  chemical  element ; compounds 
of  this  kind  are  called  saturated;  ethane  is  an  example,  C2H6. 

In  other  cases,  where  there  exists  double  or  treble  linkage 
between  two  adjacent  carbon  atoms  the  compound  is  called 
unsaturated ; acetylene,  C2H2,  is  an  example. 

It  should  be  noted,  however,  that  double  or  treble  linkage  does  not  imply 
greater  molecular  stability  — quite  the  contrary,  it  implies  less.  In  a complex 
compound  of  this  kind  when  powerful  chemical  agents  are  applied,  the  subdivis- 
ion of  the  molecule  is  most  likely  to  occur  at  the  point  where  double  or  treble 
linkage  exists.  This  view  is  also  sustained  by  certain  experiments  of  R.  Schiff. 
These  have  shown  that  in  case  of  doubly  linked  carbon  atoms  the  atomic  vol- 
ume of  the  carbon  is  slightly  greater  than  in  singly  linked  carbon  atoms. 


Molecular  Structure  of  Compounds. 

Within  the  last  few  years,  great  progress  has  been  made  in  the 
acquisition  of  knowledge  with  respect  to  the  molecular  structure 
of  certain  organic  compounds ; yet  in  the  vast  majority  of  cases 
this  molecular  structure  is  yet  unknown. 

The  inorganic  compounds  have  been  arranged  in  a certain  order  in  accordance 
with  their  natural  affiliations,  and  though  when  such  arrangement  is  made  some 
gaps  appear,  these  gaps  are  of  great  service  in  that  they  suggest  that  many 
more  compounds  than  those  yet  recognized  or  described  may  be  hereafter  pro- 
duced. 

To  the  organic  compounds  the  same  statement  may  be  applied.  Gaps  in 
their  list  point  out  avenues  for  future  discovery  in  organic  chemistry. 


In  studying  any  chemical  compound  the  investigator  desires  to 
learn  : 

First,  its  qualitative  composition. 

Second,  its  quantitative  composition.  (This  includes  the  per- 
centage amounts  of  the  components,  or  more,  the  number  of 
atoms  in  a molecule.) 

Third,  the  inner  atomic  grouping  or  arrangement. 


8 


CARBON  COMPOUNDS. 


The  determination  of  the  qualitative  or  quantitative  composi- 
tion is  not  very  difficult  in  cases  of  most  compounds  whether 
inorganic  or  organic. 

But  it  is  often  very  difficult  — in  some  cases  it  is,  at  present, 
impossible  — to  determine  the  atomic  groupings  or  even  the  mole- 
cular weight  of  a compound.  In  case  of  many  inorganic  sub- 
stances the  molecular  weight  now  accepted  may  be  materially 
changed  hereafter. 

One  of  the  best  guides  in  the  determination  of  the  molecular  weight  of  a sub- 
stance is  its  vapor  density.  Now  a larger  proportion  of  organic  compounds 
than  of  inorganic  compounds  may  be  changed  to  vapor  without  decomposition. 
Hence,  the  true  molecular  weight  is  known  in  more  cases  in  organic  chemistry 
than  in  inorganic  chemistry.  But  there  are  some  organic  substances,  as  sugar 
for  example,  which  cannot  be  changed  to  vapor  without  decomposition.  Thus 
their  molecular  weight  cannot  be  determined  by  the  method  stated. 

In  some  cases  the  molecular  formula  may  be  determined  by  other  means. 

The  determination  of  the  inner  atomic  grouping  of  substances  has  been  car- 
ried on  with  what  may  be  considered  a high  degree  of  success  in  case  of  many 
of  the  carbon  compounds  ; but  the  methods  employed  are  so  various  as  to  make 
it  impracticable  to  undertake  a discussion  of  them  here. 

The  fact  that  carbon  forms  so  large  a nnmber  of  compounds,  many  of  which 
differ  one  from  another  by  the  addition  of  easily  transferred  radicles,  makes 
comparisons  of  chemical  and  physical  properties  easier  than  in  the  case  of 
the  atoms  of  inorganic  chemistry.  Thus  organic  chemistry  seems  to  be  likely 
to  throw  great  light  upon  the  field  of  inorganic  chemistry. 


Organic  Compounds  Classified. 

The  difficulty  of  classifying  organic  compounds  is  of  course 
very  great.  This  is  due,  first , to  their  great  number ; second , to 
the  many  relationships  of  one  and  the  same  substance ; third,  to 
the  relative  imperfection  of  our  acquaintance  with  the  most  of 
them. 

Those  organic  substances  with  which  chemists  are  best 
acquainted  are  arranged  for  discussion  in  many  different  ways. 
But  they  are  almost  always  arranged  in  four  great  groups  : 

ist.  Fatty  compounds.  This  group  includes  most  of  the  open-chain  com- 
pounds. They  are  usually  considered  as  derivatives  of  marsh  gas,  CH4. 
(They  are  not  necessarily  oily  or  greasy  — they  may  be  quite  otherwise.) 

2d.  Aromatic  compounds.  These  are  closed  chain  compounds.  Many  of 
them  contain  one  or  more  benzene  nuclei,  (Cc) 

3d.  Other  less  easily  classified  vegetable  matters. 

4th.  Other  less  easily  classified  animal  matters. 


ORGANIC  AND  INORGANIC  COMPOUNDS. 


9 


Carbon  and  Silicon  Compared, 

The  silicon  atom,  like  the  carbon  atom,  has  four  points  of  attraction.  Silicon 
also  forms  certain  compounds,  closely  analogous  to  well  known  organic  com- 
pounds, the  difference  consisting  merely  in  a replacement  of  carbon  by  silicon. 
Undoubtedly,  silicon  forms  a vast  number  of  compounds  — witness  the  great 
variety  of  silicious  rocks  known.  Indeed  silicon  is  the  characteristic  element  of 
the  mineral  kingdom  as  carbon  is  of  the  organic  kingdoms.  But  chemists 
know  less  of  the  structure  of  silicon  compounds  because  these  cannot  be  easily 
dissolved  or  volatilized  or  decomposed  as  carbon  compounds  can. 


CHAPTER  IT. 


THE  STUDY  OF  ORGANIC  COMPOUNDS. 

Ultimate  Analysis  and  Proximate  Analysis. 

In  the  study  of  a given  organic  compound,  there  may  be  at 
least  three  different  kinds  of  work  to  be  conducted.  First , the 
substance  itself  should  be  produced  or  prepared  in  a pure  condi- 
tion, i.  e.,  free  from  admixture  with  any  other  substance.  Second , 
the  qualitative  and  quantitative  composition  should  be  learned  ; 
it  is  comparatively  easy  to  determine  the  percentage  proportions 
of  the  different  elements  making  up  the  molecule.  Third , the 
arrangement  of  atoms  in  the  molecule  should  be  learned  ; this  is 
often  a very  difficult  task.  To  secure  the  knowledge  desired,  a 
vast  amount  of  chemical  work  must  be  done,  and  the  results  of 
such  work  must  be  carefully  compared  and  finally  employed  in  a 
logical  way. 

Most  organic  compounds  contain  two  or  more  of  the  following  elements  : 
carbon,  hydrogen,  oxygen,  nitrogen,  sulphur,  phosphorus.  Many  artificial 
organic  compounds  may  contain  in  addition  to  two  or  more  of  those  already 
mentioned,  one  or  more  of  the  halogens,  chlorine,  bromine,  iodine.  Further, 
many  organic  compounds  may  contain  one  or  more  of  the  non-metals,  or  even 
of  the  metals. 

The  analysis  of  organic  compounds  is  of  two  kinds  : ultimate 
analysis  and  proximate  analysis. 

. In  ultimate  analysis,  the  several  elementary  constituents  of  an 
organic  substance  are  detected,  and  their  amounts  determined. 

In  proximate  analysis,  one  or  several  radicles,  present  in  the 
compound,  are  isolated.  (In  another  kind  of  proximate  analysis, 
one  or  more  distinct  chemical  compounds,  existing  in  a mixture, 
may  be  separated  as  individuals  and  their  amounts  determined.) 

Ultimate  Analysis. 

The  ultimate  analysis  of  an  organic  compound  may  involve 
several  sets  of  processes. 

(io) 


ULTIMATE  ANALYSIS. 


I 


First  Process,  the  determination  of  carbon  and  hydrogen. 
This  is  usually  conducted  by  a single  operation. 

Second  Process,  the  determination  of  nitrogen. 

Third  Process,  the  determination  of  sulphur. 

Fourth  Process,  the  determination  of  phosphorus. 

Fifth  Process,  the  determination  of  chlorine  or  other  halogen. 
Sixth  Process  or  Processes,  the  determination  or  determina- 
tions of  other  non-metals  or  metals. 

Oxygen  is  usually  determined  by  difference;  that  is,  by  sub- 
tracting the  sum  of  the  other  components  from  the  total. 

The  Determination  of  Carbon  and  Hydrogen . This  is  usually  accomplished 
by  oxidizing  the  elements  mentioned,  into  carbon  dioxide,  C02,  and  water, 
H20,  respectively. 

The  operation  is  usually  conducted  in  a special  apparatus.  The  apparatus 
consists  essentially  of  four  parts  : First , a combustion  furnace.  It  is  com- 
posed of  a set  of  supports  ; these  are  for  the  tube  (usually  of  glass,  sometimes  of 
porcelain,)  in  which  the  substance  to  be  tested  is  burned.  It  has  also  a set  of  gas 
burners  capable  of  heating  the  combustion  tube  and  its  contents.  Second , the 
combustion  tube.  It  is  intended  to  contain  a mixture  of  the  substance  to  be 
tested  and  some  oxidizing  agent  (such  as  cupric  oxide,  CuO,  or  lead  chromate, 
PbCr04,)  which  easily  furnishes  oxygen  to  the  organic  substance  under  exami- 
nation. Sometimes  a small  quantity  of  potassium  chlorate  (which  is  easily 
made  to  liberate  oxygen)  is  placed  at  the  rear  end  of  the  tube.  Third , the  rear 
end  of  the  tube  is  often  supplied  with  a current  of  oxygen  gas  from  a gas  holder. 
Of  course  the  gas  must  pass  through  purifiers  before  use,  that  is,  it  must  be 
freed  from  carbon  dioxide  and  moisture  before  it  is  used.  Fourth , the  absorp- 
tion apparatus.  At  its  forward  end  the  combustion  tube  connects  with  a set  of 
bulbs,  one  or  more  to  absorb  the  water,  and  one  or  more  to  absorb  the  carbon 
dioxide,  produced  by  the  combustion.  These  tubes  are  usually  weighed  before 
and  after  a given  test.  Any  gain  in  weight  of  the  one  set  is  due  to  water 
absorbed  and  this  is  referable  to  hydrogen  of  the  original  organic  substance. 
Likewise  anv  gain  in  weight  of  the  other  set  is  due  to  carbon  dioxide  absorbed, 
and  this  is  referable  to  the  carbon  of  the  organic  substance. 

Determination  of  Nitrogen.  Absolute  Method.  This  method  depends  upon 
such  a combustion  of  the  organic  matter  as  will  separate  nitrogen  in  the  gase- 
ous form,  any  other  substances  produced  being  retained  by  suitable  absorption 
tubes.  The  nitrogen  is  then  carried  on  to  a glass  measuring  tube.  From  the 
amount  of  nitrogen  gas  obtained  in  the  measuring  tube,  the  amount  in  the 
organic  substance  under  investigation  is  determined. 

Determination  of  Nitrogen.  Soda-Lime  Method.  By  this  method,  the 
organic  matter  is  heated  in  a combustion  tube  in  contact  with  a peculiar  mix- 
ture of  sodium  hydroxide  and  calcium  oxide,  called  soda-lime.  This  powerful 
alkaline  material  withdraws  carbon  and  oxygen  from  the  organic  matter  to  form 
sodium  carbonate  or  calcium  carbonate,  or  both.  At  the  same  time  the  nitro- 
gen and  hydrogen  of  the  organic  substance  form  ammonia  gas,  NH3.  This  gas 
is  carried  forward  to  a suitable  absorption  apparatus,  containing  sulphuric  acid 


12 


CARBON  COMPOUNDS . 


or  hydrochloric  acid,  by  which  it  is  retained.  Subsequently,  the  amount  of 
ammonia  is  learned  by  usual  methods  of  analysis.  Thence,  the  amount  of 
nitrogen  in  the  original  compound  may  be  computed. 

Determination  of  Nitrogen.  Wanklyn  Method.  This  method  depends  upon 
the  fact  that  when  nitrogenous  organic  substances  are  boiled  in  an  alkaline 
solution  of  potassium  per-manganate,  this  salt  accomplishes  a special  kind  of 
oxidation.  It  leaves,  however,  the  nitrogen  and  the  hydrogen  in  a form  such  that 
they  combine  to  produce  ammonia  gas.  In  Wanklvn’s  method  this  ammonia 
gas  is  distilled  from  the  liquid  containing  it  and  caught  in  a receiver.  The 
amount  of  ammonia  in  the  receiver  is  determined  by  the  depth  of  color  it  pro- 
duces in  the  Nessler  solution. 

Determination  of  Nitrogen.  The  Kjeldahl  Method.  In  this  process  the 
organic  matter  is  decomposed  by  sulphuric  acid  in  presence  of  powdered  zinc 
under  the  influence  of  heat.  The  zinc  liberates  hydrogen  in  such  a form  that  it 
combines  with  the  nitrogen  to  form  ammonia  gas.  The  latter  substance,  how- 
ever, immediately  unites  with  the  sulphuric  acid  to  form  ammonium  sulphate. 
The  liquid  mass  is  subsequently  distilled  with  sodium  hydroxide.  The  ammo- 
nia being  expelled  and  steam  being  driven  off,  the  two  condense  together  as  a 
clear  liquid.  In  this  liquid,  ammonia  may  be  determined  volumetrically  by  a 
solution  of  standard  acid. 

Determination  of  Sulphur.  One  method  is  to  fuse  the  material  with  potas- 
sium hydroxide  and  potassium  nitrate.  The  sulphur  is  oxidized  into  a sulphate, 
which  may  be  subsequently  detected  and  determined  by  the  use  of  barium  chlo- 
ride. 

Another  method  (suitable  for  detection  rather  than  determination)  is  to  fuse 
the  organic  compound  with  potassium  hydroxide  alone:  potassium  sulphide 
results.  By  placing  the  solid  mass  upon  a clean  silver  coin,  the  silver  becomes 
darkened  from  the  formation  of  silver  sulphide. 

Another  method  is  to  fuse  the  organic  compound  with  potassium  carbonate. 
A potassium  sulphide  is  formed  which  is  capable  of  giving  a purple  coloration 
with  sodium  nitro-prussiate. 

Determination  of  Phosphorus.  The  ordinary  method  is  to  fuse  the  material 
with  potassium  hydroxide  and  potassium  nitrate.  The  process  is  oxidizing; 
the  phosphorus  being  turned  into  a phosphate.  This  is  subsequently  detected 
and  determined  by  the  ammonium  molybdate  or  other  well-known  methods. 

Determination  of  Chlorine  and  other  halogens.  For  this  purpose  many  proc- 
esses may  be  employed,  the  general  effort  being  to  separate  the  chlorine  or 
other  halogens  from  the  original  compound  and  get  it  into  the  form  of  a soluble 
chloride,  bromide,  etc.  In  this  soluble  salt  the  halogen  is  detected  and  may  be 
estimated  by  means  of  some  silver  salt. 

Determination  of  other  Elements , Metals , etc.  In  this  case  the  organic  sub- 
stance is  heated  either  alone  or  with  some  suitable  chemical  agents,  the  more 
volatile  constituents  being  expelled.  Then  the  metals  may  be  left  as  carbonates 
which  are  capable  of  subsequent  analysis  by  ordinary  methods. 

Proximate  Analysis. 

Speaking  generally,  proximate  analysis  has  for  its  purpose  the 
separation  of  certain  compounds  which  exist  in  a mixture  of  sub- 


PROXIMATE  ANALYSIS. 


13 


stances.  Thus  the  proximate  analysis  of  wheat  flour  may  have 
for  its  purpose  the  determination  of  the  several  amounts  of  starch, 
protein,  crude  fibre,  fat,  and  perhaps  other  materials  existing  in 
the  flour.  Analyses  of  this  kind  may  be  considered  as  separa- 
tions of  compounds  mechanically  associated. 

But  further,  the  term  proximate  analysis  may  be  applied  to  the 
detection  of  the  various  radicles  existing  in  a complex  organic  mole- 
cule. Incidentally  it  may  be  necessary  in  case  of  fatty  com- 
pounds, and  yet  more  in  case  of  aromatic  compounds,  to  deter- 
mine the  position  certain  radicles  hold  in  the  molecules. 

As  a very  simple  example,  a substance  having  the  ultimate 
composition  CH3N02  may  be  mentioned.  This  formula  repre- 
sents two  very  different  compounds ; the  one  is  nitro  methane, 
CH3-NO2,  the  other  is  methyl  nitrite  CH3-0-N0.  It  may  be 
necessary  to  prove  the  presence  of  the  methyl  radicle ; it  may  fur- 
ther be  necessary  to  determine  whether  the  nitrogen  is  directly 
combined  with  the  methyl  or  whether  it  is  linked  to  the  methyl 
by  an  atom  of  oxygen. 

In  the  case  in  question  the  work  is  comparatively  simple. 
Under  the  influence  of  reducing  agents  such  as  nascent  hydro- 
gen, the  nitro  compounds  yield  almost  invariably  amines,  com- 
pounds containing  the  group  NH2  in  which  the  nitrogen  is 
directly  united  to  the  alkyl  radicle. 

On  the  other  hand  nitrogen  esters  easily  yield  alcohol. 

If,  therefore,  under  the  action  of  reducing  agents  upon  the 
substances  in  question,  methylamine  remains,  it  is  evident  that 
the  original  substance  was  nitro  methane.  On  the  other  hand  if 
methyl  alcohol  is  easily  produced,  it  is  evident  that  the  original 
substance  was  methyl  nitrite. 

In  order  to  distinguish,  then,  the  inner  atomic  grouping  of  a 
complex  organic  molecule,  certain  general  methods  have  been 
devised  similar  to  those  just  described. 

The  processes  of  proximate  analysis  are  too  numerous  and 
varied  to  admit  of  compact  statement  here.  Some  of  them  are 
incidentally  presented  in  succeeding  chapters. 


CHAPTER  III. 


PROXIMATE  METAMORPHOSIS  OF  ORGANIC 

BODIES. 

The  Subject  Considered,  Primarily,  with  Respect  to  the 
Operations  Performed. 

In  the  preparation  of  a given  organic  compound,  two  general 
courses  naturally  suggest  themselves.  The  one  course  is  to  con- 
struct the  desired  compound  from  the  elements.  Such  building 
up  of  the  organic  molecule  is  often  called  organic  synthesis. 
Very  few  organic  substances  can  be  produced  in  this  way  by  the 
chemist.  Any  chemist  who  shows  how  to  build  up  a new  organic 
molecule  synthetically  from  its  chemical  elements  has  secured  a 
distinct  triumph.  In  a certain  sense,  organic  compounds  found 
in  nature  may  be  said  to  be  formed  by  synthesis  (upon  close 
examination,  however,  this  statement  must  be  accepted  with 
some  limitations). 

In  many  cases  an  organic  compound  is  obtained  by  the  chemist 
by  mere  processes  of  purification,  or  separation  from  a mixture 
containing  it,  found  in  animal  or  vegetable  substances.  The 
preparation  of  cane  sugar  from  the  sugar  cane  or  from  the  sugar 
beet,  is  an  example. 

In  a great  many  cases,  an  organic  compound  is  produced  by 
chemical  operations  performed  upon  some  other  compound  found 
in  nature.  Sometimes  the  operation  represents  the  production  of 
a less  complex  artificial  organic  compound  from  a more  complex 
natural  compound. 

General  List  of  Methods. 

An  organic  compound  may  be  formed  : 

(a)  By  a direct  combination  of  elements  — organic  synthesis  ; 

(b)  By  the  addition  of  an  element  or  a radicle  to  a compound  already 
formed ; 

(H) 


PROXIMATE  METAMORPHOSIS. 


15 


(c)  By  the  substitution  of  one  or  more  elements  oivadicles  in  the  place  of 
suitable  constituents  of  a given  organic  compound  ; 

(d)  By  the  withdrawal  of  one  or  more  elements  or  radicles,  by  the  influence 
of  some  chemical  agent  having  affinity  for  them ; 

(e)  By  processes  analogous  to  fermentation,  digestion,  and  the  like,  carried 
on  under  the  influence  of  living  beings  — of  the  higher  animals  or  plants  on 
the  one  hand,  or  of  microbes  on  the  other; 

(f)  By  the  influence  of  certain  forms  of  energy,  like  that  of  heat  in  processes 
of  fractional  or  of  destructive  distillation  ; or  like  that  of  electricity  in  the  pro- 
cesses of  electrolysis. 

Special  Results  Sought. 

Among  the  chief  operations  to  be  performed,  the  following 
should  be  kept  clearly  in  mind.  The  chemist  may  need  : 

(a)  To  add  or  to  subtract  oxygen  from  a compound ; 

(b)  To  add  or  to  subtract  hydrogen  from  a compound ; 

(c)  To  add  or  to  subtract  a halogen  from  a compound ; 

(d)  To  add  or  to  subtract  hydroxyl,  HO,  from  a compound; 

(e)  To  add  or  to  subtract  combined  water  (as  distinguished  from  hygro- 
scopic water)  from  a compound  ; 

(f)  To  unite,  by  replacement  or  otherwise,  an  acid  radicle  with  a compound, 
or  to  withdraw  such  a radicle  ; 

(g)  To  secure  the  ordinary  action  of  an  alkali  upon  a compound,  or  to  with- 
draw an  alkali  metal ; 

(h)  To  provide  for  promptly  taking  up  subordinate  products  of  an  operation, 
so  that  such  products  may  not  interfere  later; 

(i)  To  perform  certain  special  operations,  not  easily  classified  or  described, 
except  in  large  detail. 

1.  Oxygen  may  be  added  to  organic  compounds  by  the  mere 
action  of  atmospheric  air  at  ordinary  temperature  or  at  high  tem- 
perature, or  by  means  of  ozone,  or  by  oxidizing  compounds  like 
hydrogen  dioxide,  nitric  acid,  or  peroxide  of  lead,  or  by  oxidizing 
mixtures  like 

Caustic  alkalies  and  moist  silver  oxide, 

Sulphuric  acid  and  potassium  dichromate, 

Sulphuric  acid  and  manganese  dioxide, 

Hydrochloric,  sulphuric,  or  nitric  acid,  either  of  these  with  potassium  chlo- 
rate. 

Potassium  hydroxide  or  sodium  hydroxide,  as  solids,  when  fused  with  certain 
organic  compounds,  have  an  oxidizing  action.  A somewhat  similar  action  is 
illustrated  below  (but  without  fusion)  : 

C2H5OH  + KOH  = KOOC.CH3  + 2H2 

Ethyl  Potassium  Potassium  Water, 

alcohol,  hydroxide,  acetate, 


i6 


CARBON  COMPOUNDS. 


Chlorine  and  the  other  halogens  in  presence  of  water  tend  to  withdraw  hydro- 
gen, liberating  oxygen  — thus  their  action  becomes  oxidizing. 

2.  Oxygen  may  be  withdrawn  from  organic  compounds  by 
reducing  agents.  Nascent  hydrogen  exercises  reducing  action, 
drawing  from  organic  compounds  their  oxygen  or  chlorine  or 
other  electro-negative  elements.  Thus,  nascent  hydrogen  may 
reduce  nitro-substitution  compounds  to  amines ; for  example, 
nitrobenzene  to  phenylamine,  called  aniline,  as  follows : 

(C6H5)N02  + 3H2  = (C6H5)NH2  + 2H2o 

Nitrobenzene  Aniline 

The  hydrogen  may  be  generated  by  the  use  of  zinc  and  sul- 
phuric acid,  or  by  zinc  and  sodium  hydroxide,  or  by  iron  filings 
with  acetic  acid,  or  by  other  methods. 

Metallic  elements  even  have  similar  effect.  Thus,  powdered 
zinc  is  reducing.  Again,  sodium  amalgam  is  reducing. 

3.  Hydrogen  may  be  added  to  organic  compounds  or  intro- 
duced into  them. 

Thus,  aldehyde  with  sodium  amalgam  and  water  produces  ethyl 
alcohol. 

Production  of  Hydrogen : 

2H20  + 2NaHg  = H2  + 2NaOH  + 2Hg 

Production  of  Ethyl  Alcohol  from  Aldehyde  : 

c2h4o  + h2  = C2H5OH 

4.  Hydrogen  may  be  withdrawn  from  organic  compounds. 

Thus,  methyl  alcohol  and  metallic  potassium  yield  free  hydro- 
gen : 

2CH3OH  + K2  = 2CH3OK  + H2 

5.  Chlorine  and  the  other  halogens  may  be  added  to  organic 
compounds.  The  following  are  examples  : 


c2h4 

+ 

Cl2  = 

C2H4C12 

Ethylene 

Chlorine 

Ethylene 

chloride 

c6h6 

+ 

3CI2  = 

c6h6ci6 

Benzene 

Chlorine 

Benzene 

hexachloride 

PR OXIMA  TE  ME TAMORPHOSIS. 


1 7 


Phosphorus  pentachloride,  PC15,  and  phosphorus  pentabromide, 
PBr5,  are  so  unstable  that  they  easily  part  with  a portion  of  the 
halogen  present  — the  latter  then  acts  much  as  it  does  in  the 
free  condition. 

C2H40  + PC15  ==  C2H4C12  + POCl2 

Aldehyde  Phosphorus  Ethylene  Phosphorus 

pentachloride  chloride  oxychloride 

In  some  cases  the  halogens  act  substitutingly : they  replace 
hydrogen. 

6.  Chlorine  and  the  other  halogens  may  be  withdrawn  from 
organic  compounds.  Thus,  ethyl  iodide  gives  up  its  iodine  to 
powdered  zinc : 

2C2H5I  + Zn  = Znl2  + C4H10 

Ethyl  Zinc  Zinc  Butane 

iodide  iodide 

7.  The  hydroxyl  group,  HO,  may  be  withdrawn  from  organic 
compounds. 

Phosphorus  trichloride,  PC13,  phosphorus  tribromide,  PBr3, 
phosphorus  oxychloride,  POCl3,  tend  to  remove  the  hydroxyl 
group,  HO,  and  at  the  same  time  replace  it  by  the  halogen  pres- 
ent. 

3C2H5OH  + PC13  = 3C2H6C1  + H3P03 

Ethyl  Phosphorus  Ethyl  Phosphorus 

alcohol  trichloride  chloride  acid 

Hydrochloric  acid  or  hydrobromic  acid  may  have  a similar 
kind  of  action  : 

C2H5OH  + HC1  = C2H5C1  + H20 

Ethyl  Hydrochloric  Ethyl  Water 

alcohol  acid  chloride 

8.  The  hydroxyl  group,  HO,  may  be  added  to  organic  com- 
pounds. 

Thus,  methyl  bromide  and  sodium  hydroxide  react : 

CH3Br  + NaOH  = CH3OH  + NaBr 

9.  One  or  more  molecules  of  water  may  be  added  to  organic 
compounds. 

2 


1 8 


CARBON  COMPOUNDS. 


Dilute  sulphuric  acid  occasionally  leads  to  such  addition  of 
water.  Thus,  cane  sugar,  upon  long  boiling  with  dilute  sulphuric 
acid,  forms  glucose. 

C12H22On  + H20  + H2S04  . Aq  = 2(C6H1206)  + H2S04  . Aq* 

10.  One  or  more  molecules  of  water,  H20,  may  be  withdrawn 
from  organic  compounds  containing  hydrogen  and  oxygen,  even 
when  they  do  not  exist  as  water  in  the  compound. 

Concentrated  sulphuric  acid  withdraws  the  constituents  of 
water  from  ethyl  alcohol,  forming  ethylene. 

c2h5oh  + h2so4  = c2h4  + h2o  + h2so4 

11.  An  acid  radicle  may  be  added  to  an  organic  radicle. 

Thus,  nitric  acid  may  form  an  ester  — an  ethereal  salt : 

C2H5OH  + HN03  = C2H5N03  + HOH 

Ethyl  Nitric  Ethyl  Water 

alcohol  acid  nitrate 

Again,  methyl  alcohol,  distilled  with  strong  sulphuric  acid,  pro- 
duces methyl  sulphate,  an  ester,  as  follows  : 

2(CH3OH)  + H2S04  — (CH3)2S04  + 2H20 

12.  An  acid  radicle  may  be  withdrawn  from  an  organic  mole- 
cule. 

Thus,  ethyl  sulphate  upon  addition  of  potassium  hydroxide, 
parts  with  the  acid  radicle  : 

(C2H5)2S04  + 2K0H  = K2S04  + 2C2H5OH 

13.  Subordinate  products  may  be  gotten  out  of  the  way  of  the 
chief  products  of  a reaction. 

Thus  in  some  cases  where  iodine  is  used  it  forms  hydriodic 
acid,  which  would  interfere  with  a desired  reaction.  Then  the 
presence  of  nitric  acid  or  iodic  acid  or  some  similar  agent  may 
remove  the  hydriodic  acid. 

5HI  + HI03  = 3I2  + 3H20 


Aq.  signifies  an  imperfectly  defined  quantity  of  water. 


PR  OX  IMA  TE  ME  TAMORPHOSIS. 


I9 


14.  Certain  other  special  operations  may  be  noted  here  : 

By  the  addition  of  a great  variety  of  reagents,  compound  radi- 
cles may  be  transferred  from  an  organic  substance  to  some  other 
substance.  Thus,  methyl  chloride,  CH3C1,  distilled  with  potas- 
sium hydroxide,  KOH,  has  its  methyl  transferred  away  from  the 
original  molecule,  as  follows  : 

CH3CI  + KOH  = CH3OH  + KC1 

1 5.  Observe  also  that  the  oxidizing  action  of  nitric  acid  may 
be  attended  with  an  action  of  substitution. 

Thus,  nitric  acid  acts  on  benzene  to  produce  nitrobenzene,  as 
follows  : 

C6H6  + HNO3  = C6H5N02  + HoO 

Benzene  Nitric  Nitro-  Water 

acid  benzene 

1 6.  Sulphuric  acid  performs  the  operation  called  sulphona- 
tion  — adding  the  group  HS03  — for  example: 

C6H6  + H2S04  = C6H5HS03  + H20 

Benzene  Sulphuric  Benzosulphonic  Water 

acid  acid 

Heat  may  lead  to  the  union  of  certain  substances  to  produce 
organic  compounds.  For  example,  cyanogen  gas  in  a suitable 
receiver,  may  be  passed  over  potassium  under  such  conditions 
that  when  the  potassium  is  heated,  chemical  union  may  take 
place  with  the  formation  of  potassium  cyanide.  Again,  an  elec- 
tric current  of  some  sort  may  lead  elements  to  combine.  In  this 
way,  carbon  electrodes  introduced  into  a jar  containing  hydrogen 
may  be  led  under  the  influence  of  the  electric  current,  to  produce 
acetylene  by  the  union  of  carbon  and  hydrogen. 

Heat  is  an  agent  which  is  very  much  used  in  artificial  metamorphoses  of 
organic  compounds,  as  well  as  in  other  chemical  operations.  In  chemical 
operations  generally,  heat  gives  rise,  according  to  circumstances,  to  the  combi- 
nation of  chemical  substances  or  to  their  decomposition.  So  among  organic 
compounds  in  certain  cases,  heat  gives  rise  (1)  to  a union  of  somewhat  simple 
molecules  to  produce  more  complex  ones ; (2)  to  a union  such  as  develops  sev- 
eral new  molecules  from  one  complex  one  with  simultaneous  addition  of  con- 
stituents; (3)  to  a splitting  up  of  complex  molecules  into  those  less  complex. 
This  third  kind  of  operation  is  of  great  importance  in  organic  chemistry.  The 
kind  of  decomposition  which  a given  organic  molecule  undergoes,  varies  very 
much  with  the  conditions  of  the  heating.  A moderate  addition  of  heat  may 


20 


CARBON  COMPOUNDS. 


produce  one  kind  of  change,  while  a much  more  considerable  addition,  favored, 
may  be,  by  pressure  (as  when  the  organic  matter  is  heated  in  a closed  iron  tube 
or  digester),  may  produce  a very  different  sort  of  decomposition.  This  sort  of 
action  may  be  looked  upon  as  a form  of  dissociation.  Many  excellent  examples 
of  it  are  of  great  practical  importance.  Thus,  in  what  is  called  the  destructive 
distillation  of  coal  in  the  manufacture  of  illuminating  gas,  the  molecules  com- 
posing the  coal  are  decomposed  into  a vast  number  of  new  molecules,  the  gas 
derived  from  the  coal  containing  for  example,  marsh  gas,  CH4,  and  ethylene, 
C2H4.  The  tarry  liquids  contain  molecules  of  benzene,  CeH6,  anthracene, 
C14H10,  and  other  important  ones.  Again,  the  destructive  distillation  of  wood 
produces  a decomposition  of  the  molecules  of  the  wood,  giving  rise  to  the 
formation  of  molecules  of  acetic  acid,  HOOOCH3,  methyl  alcohol,  CH3OH,  as 
well  as  many  others.  The  action  of  heat  in  what  is  called  fractional  distilla- 
tion must  not  be  confounded  with  the  action  just  described. 

Fractional  Distillatioti.  The  process  of  fractional  distillation  is 
much  used  in  organic  chemistry.  When  a mixture  of  two  sub- 
stances having  different  boiling  points,  is  placed  in  a retort  and 
heated  moderately,  it  is  found  that  the  boiling  point  of  the  mix- 
ture rises  by  more  or  less  distinct  steps.  A series  of  different 
distillates  is  produced.  If  the  distillates  are  received  in  separate 
bottles,  according  with  each  changing  step  of  boiling  point,  the 
bottles  may  be  found  to  contain  distinctly  separate  substances. 
Thus,  a mixture  of  ethyl  alcohol  and  water  distilled  in  a flask, 
gives  different  distillates.  The  earlier  distillates  are  richer  in 
alcohol.  The  later  distillates  are  nearly  pure  water. 

This  process  of  fractional  distillation  is  much  used  in  the  arts  as  well  as 
in  organic  chemistry. 

In  the  treatment  of  crude  petroleum,  fractional  distillation  is  skilfully  used. 
A given  petroleum  as  it  flows  from  the  earth,  is  a mixture  of  a very  large  num- 
ber of  hydrocarbons.  By  skilful  and  repeated  fractional  distillations  these  may 
be  separated  one  from  another  so  that  each  one  of  the  several  selected  distillates 
may  be  found  to  be  a practically  homogeneous  compound. 

To  recapitulate  under  the  head  of  agents  (either  reagents  or 
forces)  rather  than  under  the  head  of  operations  : 

1.  Oxygen  is  oxidizing.  The  oxygen  may  be  added  or  it  may 
oxidize  hydrogen  and  expel  it  as  water. 

2.  Ozone  acts  like  oxygen  only  more  energetically. 

3.  Hydrogen  peroxide,  H202,  acts  like  ozone. 

4.  Hydrogen,  especially  in  the  nascent  state,  is  reducing.  It 
withdraws  oxygen  and  the  halogens. 


PR  OX  IMA  TE  ME  TAMORPHOSIS. 


21 


5.  Powdered  zinc  acts  like  hydrogen.  (In  certain  cases  the 
zinc  itself  enters  the  molecule.) 

6 The  alkali  metals,  or  their  amalgams,  act  like  zinc.  (In 
certain  cases  these  metals  enter  the  molecule.) 

7.  The  halogens  enter  in  a substituting  way  (taking  the  place 
of  hydrogen).  Or  they  add  themselves  to  the  molecule. 

8.  Phosphorus  trichloride,  also  bromide,  and  phosphorus  oxy- 
chloride, POCI3,  may  remove  the  hydroxyl  group,  HO,  and  they 
may  replace  it  by  the  halogen  present. 

9.  Phosphorus  pentachloride,  also  bromide,  may  set  free  a 
part  of  the  halogen  to  act  directly. 

10.  Hydrochloric  acid  may  act  simply  as  an  acid  to  combine 
with  suitable  radicles. 

it.  Nitric  acid  may  act  simply  as  an  acid  to  combine  with 
suitable  radicles. 

Or  it  may  act  as  an  oxidizing  agent. 

Or  it  may  act  substitutingly,  forming  nitro-compounds. 

Or  it  may  destroy  subordinate  interfering  products. 

12.  Sulphuric  acid  may  act  simply  as  an  acid  to  combine  with 
suitable  radicles. 

Or  it  may  withdraw  water  from  compounds  containing  hydro- 
gen and  oxygen. 

Or  it  may  sulphonate  compounds,  substituting  the  group  HS03. 

13.  Sodium  hydroxide  or  potassium  hydroxide  may  act  simply 
as  alkalies. 

Or  they  may,  when  fused  dry,  have  an  oxidizing  action. 

Or  in  case  of  nitrogen  compounds  they  may  withdraw  the 
elements  C and  O (to  form  alkaline  carbonates)  thus  liberating 
ammonia  gas. 

14.  Potassium  permanganate, 

Potassium  dichromate, 

Cupric  oxide,  may  act  as  oxidizing  agents. 

15.  Ferments  of  a specific  character  may  produce  specific 
compounds. 

1 6.  Heat  acts  dissociatively. 

17.  Electricity  may  stimulate  union  of  elements  ; oftener  it 
may  act  dissociatively. 


CHAPTER  IV. 


PROXIMATE  METAMORPHOSIS  OF  ORGANIC 
COMPOUNDS. 


The  Subject  Considered  with  Reference  to  the  Products 

Obtained. 


It  has  already  been  stated  as  a fundamental  principle  of 
organic  chemistry,  that  certain  organic  radicles  act  in  a general 
way  like  elements.  Just  as  different  metals  form  halogen  com- 
pounds, oxygen  compounds,  hydroxides,  sulphates,  nitrates,  etc., 
so  do  the  electro-positive  organic  radicles.  It  should  be  noted  that 
in  inorganic  chemistry  certain  elements  are  called  electro-negative 
(although  this  classification  is  based  upon  relative  characteristics 
rather  than  upon  absolute).  So,  in  organic  chemistry,  certain 
radicles,  generally  oxyhydrocarbons,  act  like  non-metals.  Thus,  as 
the  non-metals  of  inorganic  chemistry  tend  to  form  acid  anhydrides 
and  then  acids  and  then  enter  into  the  formation  of  salfs  (in  this 
case,  by  union  with  electro-positive  elements  or  compounds) ; so 
those  organic  radicles  which  correspond  to  non-metals,  may  form 
salts  with  those  organic  radicles  that  correspond  to  metals. 
These  analogies  may  be  easier  comprehended  by  study  of  the 
following  table  : 


Methyl,  CH3 

Methyl  hydride,  CH3H 

Methyl  chloride,  CH3C1 

Methyl  ether,  (CH3)20 

Methylethyl  ether,  CH3C2H50 
Methyl  alcohol,  CH3OH 


Acetyl,  — OC-CH3 

Acetic  aldehyde,  HOC-CH3 
Acetyl  chloride,  C10C;CH3 


Acetic  acid,  HOOOCH; 


Methyl  — acetate 
Crl0 — O — OC’CH3 


K20  + 2(H0N02)  = 2K0N02  -f  h2o 

Potassium  oxide  Nitric  acid  Potassium  nitrate 


(CH3)20  + 2(HOOC-CH3)  = 2(CH3OOC*CH3)  -f  h2o 
Methyl  oxide  Acetic  acid  Methyl  acetate 


(22) 


PR  OX  IMA  TE  ME  TAMORPHOSIS. 


23 


Certain  forms  of  transformation  of  one  organic  compound  into 
another,  are  stated  below.  It  may  be  noted,  first , that  only  the 
easier  understood  transformations  are  represented  ; and  second, 
that,  as  far  as  possible,  only  two  sets  of  radicles  are  employed  in 
the  examples  (the  first  set  commencing  with  ethyl,  the  second  set 
commencing  with  acetyl.) 

(1)  The  hydrocarbon  radicles  are  viewed  as  the  starting  points. 
Thus,  the  hydrocarbon  radicle  ethyl,  C2H5,  the  equivalent  of  a 
metal,  is  capable  of  nearly  all  the  transformations  mentioned 
below.  These  radicles  are  often  called  alkyl  radicles . 

(2)  Hydrides  are  formed  b^  the  mere  union  of  hydrogen  with 
hydrocarbon  radicles.  Thus,  ethyl  forms  ethyl  hydride,  C2H5H, 
called  ethane. 

(3)  Halogen  compounds  are  formed  by  direct  union  of  halogen 
elements  (chlorine,  bromine,  iodine,  fluorine,)  with  the  organic 
radicles.  Thus,  ethyl  forms  ethyl  chloride,  C2H5C1. 

(4)  Oxides , called  ethers , are  formed  after  the  water  type. 
Thus,  ethyl  forms  the  oxide  (C2H5)20,  called  ethyl  ether.  Ethers 
are  called  simple  when  but  one  kind  of  radicle  is  present.  If  more 
than  one  kind  of  radicle  is  present,  they  are  called  mixed.  Thus, 
methyl  and  ethyl  may  form  together  an  oxide  which  is  called  a 
mixed  ether,  CH3C2H50,  methylethyl  ether. 

(5)  Hydroxides,  called  alcohols,  are  formed  also  after  the  water 
type.  In  forming  alcohols,  only  one-half  of  the  hydrogen  of 
water  is  replaced  by  the  organic  radicle.  Thus,  ethyl  alcohol  is 

c2h5oh. 

The  ordinary  alcohols  are  of  three  kinds,  called  primary,  sec- 
ondary, and  tertiary.  The  classification  is  based  on  the  structure 
of  the  alcohol ; their  recognition  is  experimentally  based  on  the 
products  derived  from  their  subsequent  oxidation. 

(6)  Organic  acids.  Any  given  organic  acid  contains  one  or 
more  molecules  of  carboxyl,  HOOC — . Thus  acetic  acid  is 
HOOCCH3. 

The  hydrogen  atom  of  the  carboxyl  is  replaceable  by  metal  so 
as  to  form  a salt. 

Thus  acetic  acid  forms  potassium  acetate,  KOOC*CH3. 


24 


CARBON  COMPOUNDS. 


The  following  partial  list  is  worthy  of  note  : 


Formic  acid,  HOOOH 

Acetic  acid,  HOOOCH3 

Propionic  acid,  HOOOC2H5 

Butyric  acid,  HOOOC3H7 


Potassium  formate,  KOOC-H 

Potassium  acetate,  KOOOCH3 

Potassium  propionate,  KOOC’C2H5 

Potassium  butyrate,  KOOOC3H7 

etc. 


They  also  form  organic  salts  which  are  known  as  esters.  A 
simple  example  is  found  in  ethyl  acetic  ester,  ethyl  acetate, 
(C2H5)OOC-CH3. 

(7)  Aldehydes , are  characterized  by  one  molecule  of  carboxyl, 
CO,  acting  as  an  intermediate  link  of  connection  between  the 
hydrogen  on  the  one  hand  and  a hydrocarbon  radicle  on  the 
other : 

Acetic  aldehyde,  C2H40  = CH3(CO)H 

H 

HC— C— H 
H O 


(8)  Ketones , have  an  oxide  of  carbon,  carbonyl,  CO,  acting  as 
an  intermediate  link  of  connection  between  two  radicles.  (The 
radicles  may  be  alike  or  different.)  Thus,  the  ordinary  ketone 
known  as  acetone,  or  methyl  ketone,  is  CH3COCH3. 

H H 

Methyl  ketone  (acetone),  CH3-COCH3,  HC— C— CH 

H O H 


(9)  Triad  nitrogen  ( phosphorus , arsenic , antimony ,)  compounds. 
These  are  called  amines  (phosphines,  arsines,  stibines,)  amides, 
imides,  amic  acids,  ureas  (and  others.) 

The  inorganic  types  are  ammonia  gas,  NH3,  phosphine,  PH3, 
arsine,  As  H3,  stibine,  Sb  H3. 


Examples:  Menthylamine,  NH2  CH3, 


H 

H H HCH 


N 


Formamide,  NH2*COH, 


H 

H H CO 


N 


PR  OX  IMA  TE  ME  TA  MORPHOSIS. 


25 


Carbimide,  NH*CO, 


Carbamic  acid,  NH2*COOH, 


Urea,  NH2-CONH2, 


H H O H H 


N N 


Sulphourea,  NH2-CS-NH2, 


H H S H H 


N N 


Methylurea,  NH  CH3-CO-NH2, 


H 

H HCH  O 

I I c 


N 


(10)  Pentad  nitrogen  ( 'phosphorus , arsenic , antimony ,)  com- 
pounds. These  are  substituted  ammonium  (phosphonium,  arso- 
nium,  stibonium,)  salts,  such  as  halides  and  ternary  salts. 

The  inorganic  types  are  ammonium  chloride,  NH4C1,  ammonium 
nitrate,  NH4  N03,  ammonium  sulphate,  (NH4)2S04,  ammonium 
phosphate,  (NH4)3P04,  etc. 

H 

Examples:  Methylammonium  chloride,  NH3CH3*C1,  H H H HCH  Cl 

I I 1 1 I 

N 

Methylammonium  nitrate,  N Me4  N03 
Ethylammonium  sulphate,  (N  Et4)2  SO4 


(11)  Sulphonic  compounds.  Compounds  containing  one  or 
more  groups  of  the  radicle,  HS03,  directly  united  to  the  hydrocar- 
bon radicle. 

H 

H | 

Example : Methyl  sulphonic  acid,  CH3*S03H  HCH  O O O 

1 Mill 

s 


26 


CARBON  COMPOUNDS. 


Note. — Sulphonic  compounds  must  be  carefully  distinguished  from  organic 
sulphates  and  sulphites,  for  example  from  such  salts  as  methyl  sulphate, 

(CH3)2S04 

(12)  Nitro-compounds.  Compounds  containing  one  or  more 
groups  of  the  radicle  N02,  directly  united  with  the  hydrocarbon 
radicle. 

H 

Example : Nitro-methane,  HC N02 

H 


Note. — Nitro-compounds  must  be  carefully  distinguished  from  organic 
nitrites  and  nitrates. 

H 

Examples:  Methyl  nitrite  (an  isomer  of  nitromethane),  HC — O — NO 

H 

H 

Methyl  nitrate,  HC — O — NO2 
H 


( 1 3)  Organo-metallic  bodies  are  formed  by  a proper  combina- 
tion of  certain  metals  with  compound  radicles.  Such  compounds 
may  assume  a great  variety  of  forms.  In  all  cases,  however,  their 
construction  is  after  the  type  of  examples  discussed.  As  it  has 
been  shown  that  in  mixed  ethers  and  esters,  more  than  one 
organic  radicle  may  be  present,  it  should  not  be  unexpected  that 
even  a metal  — the  simple  radicle  of  the  inorganic  chemist  — 
may  take  the  place  of  an  organic  radicle,  such  as  has  before  been 
called,  in  certain  cases,  the  metal  of  the  organic  chemist. 


CHAPTER  V. 


BINARY  CARBON  COMPOUNDS. 

Compounds  Containing  Hydrogen,  or  Chlorine  or  Oxygen 

or  Sulphur. 

I.  Compounds  of  Carbon  and  Hydrogen. 

Carbon  combines  with  hydrogen  in  a large  number  of  different 
proportions  and  by  a great  many  different  methods.  The  two 
elements  mentioned  thus  form  an  enormous  number  of  substances 
included  in  the  important  class  called  the  hydrocarbons. 

The  hydrocarbons  are  usually  divided  into  two  great  groups  ; 
the  one  is  called  the  fatty  or  open  chain  group,  the  other  is  called 
the  aromatic  or  the  closed  chain  group. 

Members  of  the  fatty  group  are  found  in  nature  in  petroleum 
oils  and  in  what  is  known  as  natural  gas.  Petroleum  oils  come 
to  the  surface  through  natural  crevices  or  through  artificial  wells 
bored  for  the  purpose  of  securing  them.  Natural  gas  is  obtained 
in  a similar  manner.  Petroleum,  and  natural  gas  as  well,  are 
mixtures  of  different  substances.  Certain  of  the  more  volatile 
liquids  obtainable  from  petroleum  are  known  in  commerce  under 
the  names,  naphtha,  gasolene,  benzine.  The  last  name  is  an 
unfortunate  one.  It  sometimes  introduces  a misapprehension 
from  its  close  resemblance  to  the  word  benzene,  the  latter  apply- 
ing properly  to  a hydrocarbon,  C6H6  of  the  aromatic  series. 

The  aromatic  hydrocarbons  do  not  exist  in  abundance  in  nature ; 
they  are  oftener  produced  by  the  decomposition  of  certain  organic 
substances. 

Chemists  accept  as  the  primary  substance  of  the  fatty  series,  the  compound, 
CH4,  called  marsh  gas.  By  proper  chemical  operations  leading  to  the  addi- 
tion of  elements  or  radicles,  marsh  gas  may  be  modified  or  added  to  in  such  a 
way  as  to  build  up  much  more  complex  organic  compounds  of  its  group. 

Chemists  generally  accept  as  the  primary  substance  of  the  aromatic  series 
the  compound,  CeH6,  called  benzene.  This  substance  is  a volatile  liquid.  It 

(27) 


28 


CARBON  COMPOUNDS. 


is  usually  obtained  by  the  fractional  distillation  of  the  coal-tar  produced  in  the 
manufacture  of  illuminating  gas. 

A more  extended  discussion  of  the  hydrocarbons  will  be  presented  later. 

II.  Compounds  of  Carbon  and  Chlorine. 

With  chlorine,  carbon  forms  the  compound  carbon  tetra- 
chloride, CC14.  This  substance  is  looked  upon  as  equivalent  to 
marsh  gas,  CH4,  in  which  the  hydrogen  atoms  have  been  replaced 
by  chlorine  atoms.  The  propriety  of  this  view  is  found  in  the 
fact  that  a series  of  compounds  may  be  produced,  of  which  the 
following  is  a list : 

ch4  ch3ci  CH2C12  chci3  CC14 

It  is  evident  that  this  series  represents  gradual  and  progressive 
replacement  of  hydrogen  by  chlorine. 

Compounds  similar  to  the  foregoing  may  be  formed,  in  which 
bromine  and  iodine  and  even  other  substances  are  present  in 
place  of  chlorine. 

III.  Compounds  of  Carbon  and  Oxygen. 

A word  on  this  subject  is  introduced  here  merely  to  complete 
the  classification.  The  strict  definition  of  organic  compounds, 
given  in  another  place,  excludes  the  two  compounds  of  carbon 
and  oxygen.  In  fact,  the  latter  are  usually  classified  in  the 
inorganic  department. 

Carbon  forms  but  two  compounds  with  oxygen,  carbon  monox- 
ide, CO,  and  carbon  dioxide,  C02.  The  structural  relation  of 
carbon  dioxide  to  marsh  gas — the  fundamental  compound  of 
organic  chemistry — is  very  evident.  In  the  one  case,  the  four 
points  of  attraction  of  the  carbon  atom  are  satisfied  by  two  atoms 
of  oxygen  ; and  in  the  other  case,  by  four  atoms  of  hydrogen. 

The  small  number  of  compounds  of  carbon  and  oxygen,  as 
compared  with  the  enormous  number  of  compounds  of  carbon 
and  hydrogen,  is  worthy  of  note. 

Carbon  dioxide  is  assumed  to  contain  the  radicle  CO,  called  carbonyl. 

The  compound  carbonyl  chloride,  COCb*  is  of  theoretical  interest.  In  it,  a 
partial  replacement  of  oxygen  by  chlorine  is  observed.  The  process  cor- 
responds with  that  whereby,  in  marsh  gas,  hydrogen  is  replaced  by  chlorine. 


BINARY  COMPOUNDS. 


29 


IV.  Compounds  of  Carbon  and  Sulphur. 

But  one  compound  of  these  elements  is  known,  carbon  disul- 
phide, CS2.  It  is  not  usually  considered  as  belonging  to  organic 
chemistry.  It  is  a well  known  volatile  liquid,  and  it  is  consider- 
ably used  in  the  arts. 

Its  structural  resemblance  to  carbon  dioxide  and  thence  to 
marsh  gas,  is  easily  apparent. 

It  is  assumed  to  contain  a compound  radicle,  CS,  called  thiocarbonyl.  The 
compound,  COS,  called  carbonyl  sulphide,  is  of  theoretical  interest.  It  shows 
a partial  substitution  of  sulphur  for  the  oxygen  in  carbon  dioxide,  correspond- 
ing, in  fact,  to  the  substitution  of  chlorine  for  hydrogen  in  marsh  gas  already 
adverted  to. 


V.  Compounds  of  Carbon  and  Nitrogen. 

A very  large  number  of  compounds  called  cyanogen  com- 
pounds or  cyanides,  are  recognized  as  containing  a radicle,  CN, 
called  cyanogen.  The  following  list  shows  that  this  radicle  acts 
like  a monad  element.  Indeed,  in  many  cases,  its  analogy  with 
chlorine  is  very  marked. 


Hydrocyanic  acid, 
Cyanogen  gas, 
Cyanogen  chloride, 
Cyanic  acid, 
Thiocyanic  acid, 


H(CN) 

CN(CN) 

(CN)C1 

HO(CN) 

HS(CN) 


Theoretically,  cyanogen  compounds  may  be  looked  upon  as  connected  with 
ammonia  gas,  NH3.  Thus,  the  group  hydrocyanic  acid,  HCN,  may  be  con- 
sidered as  ammonia  gas,  NH3,  in  which  three  atoms  of  hydrogen  are  replaced 
by  the  triad  radicle  CH  (called  methenyl.) 

Again,  hydrocyanic  acid,  HCN,  may  be  looked  upon  as  marsh  gas,  CH4,  in 
which  three  atoms  of  hydrogen  have  been  replaced  by  one  atom  of  the  triad 
element  nitrogen. 


Cyanogen  compounds  exist  to  some  extent  in  nature.  Thus, 
they  are  found  in  the  kernels  of  certain  fruits,  like  peaches. 
Most  of  such  compounds,  however,  are  produced  by  artificial 
processes.  They  have  two  great  characteristic  properties  ; first, 
many  of  them  are  poisonous — hydrocyanic  acid,  called  prussic 
acid,  being  one  of  the  most  dangerous  poisons  known  ; second, 
they  show  a marked  tendency  to  produce  complex  compounds 
and  highly  colored  compounds,  especially  with  metals,  like  iron 
and  other  members  of  its  group — Prussian  blue  for  example. 


30 


CARBON  COMPOUNDS. 


Certain  cyanogen  compounds  are  largely  used  in  the  arts. 
The  most  important  are  potassium  cyanide,  KCN,  and  potassium 
ferrocyanide,  K4Fe(CN)6. 

Their  general  mode  of  preparation  involves  the  use  of  animal  matters  con- 
taining at  once  carbon  and  nitrogen.  Such  matters,  when  heated  under 
proper  conditions,  undergo  decomposition,  certain  elements  being  expelled, 
and  the  carbon  and  nitrogen  entering  into  the  new  relations  appropriate  to  the 
formation  of  cyanogen  compounds. 

Potassium  ferrocyanide,  K4Fe(CN)6  . 3H20.  This  is  a very 
important  salt  in  commerce,  where  it  is  known  as  yellow prussiate 
of  potash.  It  is  manufactured  on  a large  scale  by  heating  certain 
cheap  animal  matters,  such  as  old  leather  or  leather  scraps,  with 
potassium  carbonate,  K2C03,  and  iron  filings.  The  crude  mass 
is  cooled.  Subsequently,  it  is  treated  with  water.  Thus,  potas- 
sium ferrocyanide  is  brought  into  solution.  The  clear  liquid  is 
evaporated  somewhat  and  then  allowed  to  crystallize.  Trans- 
parent yellow  crystals  of  potassium  ferrocyanide  are  thus  pro- 
duced. 

This  substance  is  largely  used  in  the  arts  for  the  manufacture 
of  potassium  cyanide  and  also  in  the  production  of  Prussian 
blue. 

Potassium  ferrocyanide,  when  added  to  ferric  salts,  gives 
rise,  at  once,  to  a deep  blue  precipitate  called  Prussian  blue, 
Fe4Fe3(CN)18.  This  compound  does  not  dissolve  readily  in  the 
presence  of  certain  salts.  When  the  latter,  however,  have  been 
removed,  it  dissolves  in  pure  water,  imparting  to  it  a deep  blue 
color.  On  the  large  scale,  Prussian  blue  is  produced  by  the  mix- 
ture of  potassium  ferrocyanide,  ferrous  sulphate,  and  chlorine 
water.  Without  the  chlorine,  ferrous  salts  afford  a much  lighter 
colored  precipitate.  The  chlorine  oxidizes  the  ferrous  compound 
to  the  ferric  form,  and  thus  affords  the  deep  blue  precipitate. 

When  potassium  ferrocyanide  alone  is  subjected  to  the  action 
of  chlorine  gas,  a new|compound,  called  potassium  ferricyanide, 
K3Fe(CN)6,  is  produced. 

Potassium  ferricyanide  is  known  as  red  prussiate  of  potash. 
With  ferric  salts,  it  gives  only  a brown  discoloration  ; but  with 
ferrous  salts,  it  gives  a deep  blue  precipitate  of  soluble  Prussian 
blue,  Fe3Fe2(CN)12,  called  Turnbull’s  blue.  There  are  at  least 


BINARY  COMPOUNDS. 


3 


three  varieties  of  Prussian  blue : the  soluble  blue,  the  insoluble 
blue,  and  Turnbull’s  blue.  They  vary  in  composition  according 
to  the  method  of  preparation.  They  are  very  much  used  in  the 
dyeing  and  printing  of  cotton  goods.  A tolerable  blue  on 
bleached  cotton  may  be  produced  by  dipping  the  bleached  cotton 
cloth  first,  in  solution  of  potassium  ferrocyanide,  and  then  in 
solution  of  ferrous  sulphate,  and,  finally,  exposing  the  goods  to 
the  oxidizing  action  of  the  atmosphere. 

In  certain  kinds  of  calico  printing,  a paste  is  produced  by 
mixing  in  water,  potassium  ferrocyanide,  tartaric  acid,  and  starch. 
The  paste  may  be  printed  upon  cloth.  Then,  upon  heating,  the 
acid  decomposes  the  ferrocyanide,  and  Prussian  blue  is  formed. 

Potassium  cyanide,  KCN.  This  substance  may  be  produced 
by  heating  potassium  ferrocyanide  either  alone  or  with  potassium 
carbonate. 

It  is  a white  salt  having  an  odor  somewhat  resembling  that  of 
peach  kernels.  It  is  much  used  in  certain  operations  connected 
with  the  processes  of  gold  and  silver  plating  by  electrolysis. 
With  certain  salts  of  silver  and  gold,  it  forms  double  salts  which 
are  soluble  and  especially  favorable  for  electro-deposition.  It  is 
largely  used  in  extracting  gold  from  certain  low-grade  ores. 

It  is  also  employed  in  the  preparation  of  hydrocyanic  acid,  also 
called  prussic  acid. 

Hydrocyanic  acid,  HCN.  This  substance,  when  in  the  anhy- 
drous form,  is  a clear  liquid  which  is  extremely  poisonous.  With 
suitable  metals,  it  forms  a series  of  salts  called  cyanides. 

It  is  an  interesting  fact  that  hydrocyanic  acid  is  capable  of  production  by  the 
direct  union  of  nitrogen  and  acetylene  under  the  influence  of  a series  of  electric 
sparks.  Since  acetylene  may  be  produced  from  its  elements  in  similar  fashion, 
it  is  plain  that  cyanogen  compounds  may  be  formed  progressively  from  the 
elements  composing  them,  and  without  the  intervention  of  vital  processes. 
This  [should  be  noted  in  connection  with  the  fact  that  ordinarily  cyanogen 
compounds^are  derived  from  potassium  ferrocyanide  which  latter  has  been  pro- 
duced by  the  use  of  an  organized  substance,  such  as  leather.  The  point  just 
now  presented  is  of  considerable  moment  in  connection  with  the  whole  theory 
of  organic  chemistry.  It  sustains  the  view  now  generally  held,  that  it  is  likely 
to  be  found  possible  to  produce  all  organic  compounds  except  the  organized 
ones  from  their  elements  without  the  intervention  of  the  processes  of  living 
animals  or  plants. 

Mercuric  cyanide,  Hg(CN)2,  is  a white  crystalline  salt  which 
may  be  produced  by  dissolving  mercuric  oxide,  HgO,  in  hydro- 


32 


CARBON  COMPOUNDS . 


cyanic  acid,  HCN.  The  substance  is  interesting,  partly  on 
account  of  the  fact  that  when  it  is  heated,  it  gives  off  cyanogen 
gas. 

Cyanogen  gas,  CN  CN,  is  a colorless  gas  having  an  odor  simi- 
lar to  hydrocyanic  acid.  It  is  distinctly  poisonous.  If  the  gas 
is  allowed  to  escape  from  a small  tube,  it  may  be  set  on  fire, 
whereupon  it  burns  with  a delicate  pinkish-blue  flame.  If  cyano- 
gen gas  is  conveyed  into  a solution  of  potassium  hydroxide  in 
water,  at  least  two  salts  are  formed,  potassium  cyanide  and  potas- 
sium cyanate.  Thus, 

2(CN)  + 2KOH  = KCN  + KOCN  + H20 

The  operation  is  analogous  to  that  whereby  potassium  chloride 
and  potassium  chlorate  are  formed,  by  the  introduction  of  chlo- 
rine gas  into  potassium  hydroxide  solution. 

Potassium  cyanate,  KOCN.  This  substance  may  be  used  for 
the  preparation  of  cyanic  acid,  HOCN,  and  thence  of  ammonium 
isocyanate  NH4OCN.  Upon  allowing  the  latter  to  rest  some 
time  in  water  solution,  it  spontaneously  decomposes  into  an  iso- 
meric substance,  urea,  HN2CONH2.  This  latter  compound  is 
very  interesting  on  account  of  its  relations  to  the  history  of 
theoretical  chemistry.  The  distinguished  German  chemist,  Fried- 
rich Woehler,  discovered  this  change  in  1828;  and  his  observa- 
tion has  ever  since  been  noted  as  a most  important  historical 
event  in  chemistry.  Urea  had  not  been  known  previously  except 
in  the  urine  of  the  higher  animals,  produced  therefore,  by  the 
influence  of  the  vital  processes ; and  moreover,  the  theory  before 
Woehler’s  discovery  was  that  organic  compounds  could  not  be 
produced  artificially.  The  foregoing  discussion  on  cyanogen  has 
shown  that  the  following  synthetical  operations  are  practicable. 

Inorganic  Synthesis  of  Urea. 

A.  Carbon  and  hydrogen  may  be  made  to  unite  directly  to  form  acetylene, 
C2H2. 

B.  Acetylene  and  nitrogen  may  be  made  to  unite  directly  to  form  hydrocy- 
anic acid,  HCN. 

C.  Hydrocyanic  acid  and  mercuric  oxide  may  be  made  to  react  so  as  to  form 
mercuric  cyanide,  HgCN. 


BINARY  COMPOUNDS. 


33 


D.  Mercuric  cyanide  by  heating  yields  cyanogen  gas,  CN*CN ; this  passed 
into  potassium  hydroxide  solution  yields  potassium  cyanate,  KOCN. 

E.  Potassium  cyanate  by  action  of  dilute  sulphuric  acid  may  be  made  to  yield 
cyanic  acid,  HOCN. 

F.  Cyanic  acid  and  ammonia  may  produce  ammonium  cyanate,  NH4OCN. 
(Note  that  while  man’s  chief  supplies  of  ammonia  are  derived  from  the  decom- 
position of  animal  and  vegetable  substances,  it  may  be  produced  without  the 
intervention  of  the  vital  processes.) 

G.  Ammonium  cyanate  may  spontaneously  turn  into  its  isomer,  urea. 

While  referring  to  cyanic  acid,  two  important  polymers  should 
be  mentioned.  They  are 

Cyanuric  acid,  H303(CN)3,  and 

Fulminic  acid,  H202(CN)2 

Fulminic  acid  combines  with  metals  to  form  highly  explosive 
compounds.  Thus,  mercuric  fulminate,  also  called  fulminating 
mercury,  is  the  violent  explosive  used  in  percussion  caps ; and 
silver  fulminate,  also  called  fulminating  silver,  is  a yet  more  dan- 
gerous explosive. 

Thiocyanic  acid,  or  sulphocyanic  acid,  HSCN,  analogous  to 
ordinary  cyanic  acid,  is  a substance  of  some  interest.  It  is  con- 
siderably used  in  commerce  in  combination  with  the  metals  in  the 
form  of  potassium  sulphocyanate,  KSCN,  and  ammonium  sulpho- 
cyanate,  NH4SCN.  Both  of  these  are  white  crystalline  salts 
readily  dissolving  in  water.  They  are  used  as  tests  in  chemistry. 
With  very  minute  quantities  of  ferric  salts,  they  produce  deep 
blood-red  colorations. 

Mercury  sulphocyanate,  HgS2(CN)2,  is  a white  powder  which 
decomposing  when  heated  yields  a very  voluminous  mass  of  mate- 
rial. Such  material  issuing  from  a suitable  wrapper,  produces  the 
curious  serpentine  mass  commonly  known  as  Pharaoh’s  serpents. 
But  the  mercurial  fumes  evolved  are  noxious. 


3 


CHAPTER  VI. 


HYDROCARBONS. 

Fatty  Series;  Aromatic  Series. 

The  hydrocarbons  are  compounds  containing  carbon  and  hydro- 
gen and  nothing  else.  (They  must  not  be  confounded  with  car- 
bohydrates.) 

Hydrocarbons  occur  in  natural  gas,  in  petroleum,  in  ozokerite, 
in  certain  plants  : india-rubber,  turpentine,  and  certain  essential 
oils  are  hydrocarbons.  Certain  hydrocarbons  are  readily  pro- 
duced by  the  decomposition  of  complex  organic  matters.  Thus, 
peat,  wood,  bituminous  coal,  salts  of  organic  acids,  etc.,  generally 
produce  hydrocarbons  (as  well  as  other  compounds)  when  heated 
without  free  access  of  oxygen.  (The  process  is  called  destructive 
distillation.) 

The  number  of  the  hydrocarbons  already  known  is  very 
great  — probably  hundreds.  Moreover  their  structure  is  such 
that  it  seems  likely  that  many  many  more  will  be  either  discov- 
ered or  produced  hereafter. 

Physically  considered  the  hydrocarbons  have  certain  general  traits.  Those 
having  small  numbers  of  carbon  atoms  are  gaseous  at  ordinary  temperatures ; 
as  the  members  having  larger  numbers  are  reached  the  substances  are  liquid ; 
later  members  are  solids. 

Thus  methane,  marsh  gas,  CH4,  is  a gas;  nonane,  is  one  of  the 

liquid  constituents  of  kerosene  oil ; the  constituents  of  paraffin  wax,  a solid, 
probably  have  at  least  as  many  as  20  atoms  of  carbon  in  the  molecule. 

Moreover  as  the  number  of  carbon  atoms  increases  there  is  apt  to  be  a definite 
rise  in  the  melting  and  boiling  points. 

The  hydrocarbons  are  but  slightly  soluble  in  water. 

Chemically  considered  the  hydrocarbons  are  rather  neutral  and  inactive. 
They  act  neither  as  acids  nor  alkalis.  Certain  powerful  chemical  influences  affect 
them  strongly,  it  is  true ; thus  they  burn  in  presence  of  oxygen  and  they  are 
capable  of  chemical  replacement  of  their  hydrogen  atoms,  step  by  step,  by  vari- 
ous radicles,  so  as  to  give  rise  to  an  immense  number  of  closely  related  com- 
pounds. 


FATTY  HYDROCARBONS. 


35 


The  formulas  of  the  known  hydrocarbons  are  such  that  these 
bodies  naturally  fall  into  groups  called  series  — the  formulas 
of  all  the  members  of  a given  series  being  expressible  by  one 
general  formula. 

In  considering  the  hydrocarbons,  as  well  as  their  derivatives, 
the  bold  distinction  between  the  fatty  group  and  the  aromatic 
group  must  be  carefully  recognized. 

General  Formulas  of  Fatty  Hydrocarbons. 


1st  series 

Cnf^2n+2 

paraffin  series 

2d  series 

C„H2n 

olefine  series 

3d  series 

CnH2n-2 

acetylene  series 

4th  series 

CnH2n— 4 

valylene  series 

5th  series 

CnH2a_6 

di-acetylene  series 

The  aromatic  hydrocarbons,  etc.,  will  be  considered  later. 

The  following  table  including  a number  of  the  important  hydro- 
carbons of  the  fatty  series  is  worthy  of  attention  : 

TABLE 

— From  Roscoe  & Schorlemmer. 

(CnH2n+2) 

(C„H2n) 

(CnH2n_2) 

Methane,  CH4 

Ethane,  C2  H6 

Ethylene,  C2  H4 

Ethine,  C2  H2 

Propane,  C3  H8 

Propylene,  C3  H6 

Propine,  C3  H4 

Butane,  C4  H10 

Butylene,  C4  H8 

Butine,  C4  H6 

Pentane,  C5  H12 

Pentylene,  C5  H10 

Pentine,  C5  H8 

Hexane,  Ce  H14 

Hexylene,  C6  H12 

Hexine,  C6  H10 

etc. 

etc. 

etc. 

Structural  Characteristics  of  Fatty  Series. 

The  several  series  of  hydrocarbons,  and  their  allied  compounds  or  deriva- 
tives, are  characterized  by  several  different  methods  of  attachment  of  one  or 
more  pairs  of  carbon  atoms. 

In  the  first  series  of  fatty  hydrocarbons  the  method  of  attachment  is  evidently 
very  simple.  Every  atom  of  carbon  is  attached  to  its  neighboring  atom  or 
atoms. of  carbon  by  one  point  or  attraction.  The  lowest  member  of  this  series 
may  have  one  atom  of  carbon,  the  higher  members  may  have  many  atoms  of 
carbon,  for  example : 

H H H H 

Butane,  C4H10,  HC — C — C — CH 
H H H H 


36 


CARBON  COMPOUNDS. 


In  the  second  series  every  member  is  characterized  by  this  peculiarity : the 
first  two  carbon  atoms  are  attached  by  two  points  of  attraction  in  common. 
Necessarily  then  the  lowest  member  must  have  at  least  two  atoms  of  carbon. 
In  the  higher  members  of  this  series  the  first  two  carbon  atoms  are  attached  as 
described  and  then  succeeding  atoms  are  attached  at  one  point  of  attraction  as 
in  the  first  series  ; for  example  : 

H 

Ethylene,  C2H4,  HC  = CH  Propylene,  C3H6,  HC  = C— CH 

H H H H H 

In  the  third  series  there  is  this  characteristic : the  first  two  carbon  atoms  are 
attached  by  three  points  of  attraction  in  common.  Evidently  in  this  series  no 
lower  member  can  exist  than  that  having  two  carbon  atoms.  The  higher  mem- 
bers of  the  series  are  characterized  by  the  first  two  carbon  atoms  united  at  three 
points  of  attraction  each  as  stated,  and  the  other  carbon  atoms  attached  by  one 
point  of  attraction  for  each  atom  of  carbon  ; for  example  : 

Acetylene,  C2  H2,  HC  = CH  Allylene,  C3H4,  HC  = C— CH3 

In  the  fourth  series  the  linkage  of  carbon  atoms  is  not  definitely  known  ; it  is 
evidently  more  complex.  For  valylene,  a member  of  this  series,  two  rational 
formulas  are  suggested  : 

Valylene,  C5H6,  CH2  = C(CII3)— C = CH  or  CH3— CH  = CH— C = CH 

In  the  fifth  series  the  characteristic  method  of  linkage  involves  two  pairs  of 
carbon  atoms,  each  pair  being  united  by  three  bonds  ; for  example  : 

Di-acetylene,  C4H2  CH  = C— C = CH 

Evidently  all  the  compounds  of  the  five  series  of  fatty  compounds  mentioned 
are  open  chain  compounds.  The  members  of  the  various  aromatic  series  all 
tend  to  form  closed  chains. 

Homologous  and  Heterologous  Compounds. 

The  various  hydrocarbons  of  a given  series  are  called  homol- 
ogous compounds.  Thus,  ethane,  propane,  butane,  are  homol- 
ogous. In  a similar  fashion  the  acids  of  this  series,  acetic  acid, 
propionic  acid,  butyric  acid,  etc.,  are  homologous  to  formic  acid. 
In  general  a given  series  of  carbon  compounds  may  possess  a 
large  number  of  sets  of  homologues. 

On  the  other  hand,  dealing  with  the  compounds  mentioned  in 
another  way,  a set  of  substances  having  the  same  stem  radicles 
but  containing  different  replacing  radicles  may  form  a heterol- 
ogous series.  Thus  from  the  radicle  ethyl  a heterologous  series 
would  include  ethane,  ethyl  chloride,  ethyl  alcohol,  ethylamine, 
acetic  acid,  etc. 


FATTY  HYDROCARBONS. 


37 


In  most  cases  each  series  is  represented  by  many  members,  and  these  in  turn 
are  capable  of  forming  many  compounds  with  other  elements  or  with  other 
compound  radicles.  Thus,  a given  member  of  any  homologous  series  may 
have  one,  two,  or  more  (according  to  circumstances),  of  its  hydrogen  atoms 
replaced  by  chlorine,  bromine,  or  other  elements,  or  by  a proper  number  of 
monad  radicles ; or  again,  in  certain  cases,  two  atoms  of  hydrogen  may  be 
replaced  by  one  atom  of  oxygen  or  of  sulphur;  while  in  other  cases,  three 
atoms  of  hydrogen  may  be  replaced  by  one  atom  of  nitrogen  or  of  arsenic  or 
of  antimony  or  of  phosphorus,  as  the  case  may  be.  Sometimes  several  sub- 
stitutions or  combinations  may  take  place  at  once.  Thus,  a given  hydrocarbon 
may  be  looked  upon  as  a kind  of  trunk  from  which  branches  may  be  extended, 
thus  giving  rise  to  very  complex  molecules. 

The  following  table  is  worthy  of  attention  as  showing  cor- 
responding compounds  of  the  fatty  series  : 

Table  of  a few  Fatty  Derivatives:  Paraffin  Series. 


Hydrocarbons. 

1 

Chlorides. 

Alcohols. 

Amines. 

Acids. 

Methane, 

ch3  h 

Methyl  chloride, 
CH3  Cl 

Methyl  alco- 
hol, CH3OH 

Methvlamine, 

ch3  h2  n 

Formic  acid, 

ch2  o2 

Ethane, 

c2  h5h 

Ethyl  chloride, 
C2  H5  Cl 

Ethyl  alcohol, 
C2  H5  OH 

Ethylamine, 

c2  h5  h2  n 

Acetic  acid, 

C2  h4  02 

Propane, 

c3  h7h 

Propyl  chloride, 
C3  H7  Cl 

Propylalcohol, 

C3  h7  OH 

Propylamine, 

c3  h7  h2  n 

Propionic  acid, 

c3  h6  o2 

Butane, 

C4  h9  h 

Butyl  chloride, 

C4  H9  Cl 

Butyl  alcohol, 
C4  h9  OH 

Butylamine, 

c4  h9  h2  n 

Butyric  acid, 

c4  h8  o2 

Pentane, 

C5  Hu  H 

Pentyl  chloride, 
C5  HUC1 

Pentyl  alcohol, 
C5  HnOH 

Pentylamine, 
C5  HnH2  N 

Pentylic  acid, 
Co  Hi0O2 

Hexane, 

c6  h13  h 

Hexyl  chloride, 
C6  H13C1 

Hexyl  alcohol, 

c6  h13oh 

Hexylamine, 

C6  h13h2  n 

Hexylic  acid, 
Ce  Hi202 

The  members  in  an  up  and  down  line  form  a homologous  series ; 
the  members  in  a right  and  left  line  form  a heterologous  series. 


CHAPTER  VII. 


FATTY  HYDROCARBONS 

Of  the  Paraffin  Series,  Cn  H2a+2. 

The  hydrocarbons  of  this  series  have  the  general  formula 
CnH2tl+2.  The  first  member  of  the  series  is  marsh  gas,  also 
called  methane,  CH4.  The  other  members  have  higher  formulas 
with  2,  3,  4,  ...  n atoms  of  carbon,  then  such  number  of  atoms 
of  hydrogen,  as  accords  with  the  demands  of  the  general 
formula.  The  following  list  presents  the  names  and  formulas 
of  some  of  the  best  known  hydrocarbons  of  this  series  : 


General  formula,  CnH2n+2  Boiling  points.  Melting  points. 


Methane, 

C h4 

Ethane, 

c2  h6 

Propane, 

c3  h8 

Butane, 

C4  H10 

Pentane, 

c5  h12 

Hexane, 

c6  h14 

Heptane, 

c7  h16 

Octane, 

c8  h18 

Nonane, 

C9  H2o 

Decane, 

C10  H22 

Undecane, 

On  h24 

Dodecane, 

C12  H26 

Tridecane, 

C13  H28 

Tetradecane, 

Ci4  H30 

Pentadecane, 

c15  H32 

Hexdecane, 

Ci6  H34 

gaseous. 

gaseous. 

gaseous. 

i°C. 

36 

69 

98 

125 

150 

173 

195 

215 

234 

253  5*5‘ 

271  10. 

solid  at  ord.  temp.  20. 


Additional  compounds  are  known  in  regular  order  (with  few 
exceptions)  from  the  compound  with  C17  up  to  that  with  C35. 
The  compound  C60H122  is  also  known. 

From  the  compound  with  C16  upward  the  hydrocarbons  are 
waxy  solids  at  ordinary  temperatures. 

(38) 


PARAFFINS. 


39 


The  table  gives  rise  to  the  following  suggestions  : 

First.  It  is  tolerably  complete  as  far  as  it  goes.  Probably, 
higher  compounds  of  the  series  may  be  discovered  hereafter. 
Probably,  also,  omitted  members  may  be  discovered. 

Second.  The  consecutive  members  differ  from  one  another  by 
the  addition  of  CH2. 

Third.  They  illustrate  one  of  the  general  laws  of  chemical 
philosophy,  namely,  the  more  atoms  in  the  molecule,  the  higher 
the  melting  point  or  boiling  point;  the  less  number  of  atoms  in 
the  molecule,  the  greater  the  volatility  or  tendency  to  assume  the 
gaseous  condition. 

Fourth.  The  addition  of  the  group  CH2  to  a given  substance 
tends  to  raise  its  boiling  point  about  twenty  or  thirty  degrees. 

Fifth.  The  ordinary  structural  formulas  are  represented  by 
the  diagrams  given  below  : 


First  Member  Second  Member  Third  Member  Fourth  Member 


H H H 

HCH  HC— CH 

H H H 


H H H 
HC— C— CH 
H H H 


H H H H 
HC— C— C— CH 
H H H H 


CH4 


ch3-ch3  ch3-ch2-ch3  ch3-ch2-ch2-ch3 


Methane  Ethane 


Propane 


Butane 


Sixth.  Each  member  of  the  series  is  viewed  as  made  up  of  a 
compound  radicle  united  with  one  atom  of  hydrogen.  Thus, 
methane,  CH4,  is  viewed  as  methyl  hydride,  CH3H  ; and  in  sub- 
sequent formation  of  other  compounds,  the  methyl,  CH3,  is 
believed  to  hold  together  as  a compound  radicle,  and  as  such  to 
be  capable  of  transfer  from  one  compound  to  another.  Similarly, 
ethane,  C2H6,  is  viewed  as  composed  of  ethyl,  C2H5,  united  with 
H.  Then,  ethane,  C2H6,  is  ethyl  hydride,  C2H5H.  The  view 
here  expressed  is  not  based  upon  a mere  mechanical  or  imaginary 
subdivision  of  the  formulas.  It  is,  rather,  a substantial  and  well 
based  induction  formed  after  a careful  study  of  organic  com- 
pounds. 

All  study  of  the  hydrocarbons  of  this  series  sustains  the  con- 
clusion that  they  are  open  chain  compounds ; but  they  are  not 
necessarily  in  all  cases  as  simple  in  their  plan  of  construction  as 
represented  in  the  diagrams  given. 


40 


CARBON  COMPOUNDS. 


Isomerism  in  the  Paraffin  Series. 

1.  Probably,  the  composition  of  marsh  gas  is  correctly  repre- 
sented as  having  one  atom  of  carbon  and  four  atoms  of  hydrogen 
somehow  arranged  about  it. 

If  the  four  atoms  of  hydrogen  are  practically  identical  in  prop- 
erties, so  that  it  is  impossible  to  distinguish  one  from  another,  a 
change  in  their  relative  positions  will  be  of  no  moment  as 
respects  the  properties  of  marsh  gas. 

If  in  a given  molecule  of  a marsh  gas,  having  the  formula  CH4, 
every  atom  of  the  substance  designated  by  H differs  appreciably 
from  every  other  atom  of  the  thing  so  designated  present  in  that 
molecule,  then  two  geometrical  isomers  of  the  compound  become 
possible. 

As  a matter  of  fact  no  isomers  of  marsh  gas  have  yet  been 
recognized.  Moreover  at  present  the  atoms  of  hydrogen  are  not 
distinguishable  one  from  another. 

While  the  general  view  presented  by  the  formula  of  marsh  gas  is  correct,  it 
gives  rise  to  some  misconception  from  the  fact  that  the  atoms  are  represented 
as  arranged  in  a plane.  Modern  views  of  chemical  molecules  have  led  to  the 
belief  that  different  parts  of  a given  molecule  may  lie  in  different  planes.  Even 
in  a case  like  marsh  gas,  it  has  been  assumed  that  the  four  points  of  attraction 
of  the  atom  of  carbon,  instead  of  lying  in  one  plane,  may  really  have  positions 
more  properly  represented' by  the  four  solid  angles  of  a tetrahedron. 

2.  Next  consider  ethane.  If  its  formula  is  constructed,  gen- 
erally speaking,  on  just  principles,  no  considerable  modification 
is  possible,  except  upon  those  stereo-chemical  grounds  already 
alluded  to.  As  a matter  of  fact,  ethane  has  not  yet  been  proved 
to  produce  isomers. 

3.  A consideration  of  the  substance  propane  shows  that,  in  the 
view  now  taken,  isomers  are  impossible.  The  three  atoms  of  car- 
bon must  be  considered  as  standing,  one  in  the  middle  position 
and  one  at  either  end.  Now  so  long  as  the  different  carbon 
atoms  are  practically  identical  and  the  different  hydrogen  atoms 
are  practically  identical,  no  isomers  can  be  expected.  None 
have  yet  been  recognized. 

4.  When,  however,  butane  is  considered,  it  is  easily  seen  that 
isomers  may  be  formed. 


PARAFFINS. 


41 


Thus,  there  are  at  least  two  ways  of  writing  the  rational 
formula  for  butane,  and  both  of  them  in  accordance  with  the 
general  open  chain  system  of  this  series. 


First  Method 


H H H H 
HC— C— C— CH 
H H H H 


ch3-ch2-ch2-ch3 

Normal  butane 


Second  Method 
H 

HCH 

H | H 

HC C CH 

H H H 


CH3-CH(CH3)*CH3 

Isobutane 


In  normal  butane,  we  have  simply  the  four  atoms  of  carbon 
arranged  in  a row.  In  isobutane,  we  have  first,  three  atoms  of 
carbon  arranged  in  a row  ; and  then,  instead  of  the  fourth  atom 
of  carbon  being  placed  at  one  end  of  the  series,  it  is  attached  to 
the  middle  atom  of  the  series  and  as  a side  branch.  The  particu- 
lar side  of  the  middle  atom,  to  which  it  is  attached,  makes  no 
difference. 

As  a matter  of  fact,  it  is  found  that  two  kinds  of  butane  can 
be  produced,  and  they  are  designated  as  normal  butane  and  isobu- 
tane, respectively. 

5.  It  has  been  said  already  that  as  the  hydrocarbons  advance 
in  their  number  of  carbon  atoms,  the  numbers  of  isomers  theo- 
retically possible  rapidly  increase.  Experiments  sustain  the 
theory. 

When  the  next  number  of  the  series,  that  is,  pentane , is  exam- 
ined, it  is  found  that  theoretically  three  isomers  are  possible.  As 
a fact,  three,  and  only  three,  have  been  found. 


First  Method 
H H H H H 
HC— C— C— C— CH 
H H H H H 


ch3-ch2-ch2-ch2-ch3 

Normal  pentane 


42 


CARBON  COMPOUNDS. 


Second  Method 
H 

HCH 

H | H H 
HC— C— C— CH 
H H H H 


CH3-CH(CH3)*CH2-CH3 
Isopentane  or  Dimethylethyl  methane 


Third  Method 
H 

HCH 
H | H 
HC— C— CH 
H | H 
HCH 
H 


C(CH3)4 

Tetramethyl  methane 


A Few  Individual  Hydrocarbons  of  this  Series. 

Methane , o?  methyl  hydride , CH4,  also  called  marsh  gas.  This 
substance  sometimes  emanates  from  crevices  in  coal  mines.  It 
often  accompanies  petroleum  as  it  issues  from  the  earth.  It  also 
forms  a part  of  the  combustible  gas  produced  by  gas  wells  and 
named  in  general  natural  gas.  It  is  a constituent  of  the  illumi- 
nating gas  manufactured  from  soft  coal. 

Marsh  gas  is  ordinarily  prepared  by  heating  sodium  acetate 
NaOOC  CH3,  with  sodium  hydroxide,  NaOH. 


Na) 

Na) 

Na2) 

} o 

+ 0 : 

= } Oo 

+ CH4 

oc-ch3  ) 

Hi 

CO  ) 

This  may  be  called  an  analytical  method  rather  than  a synthetical.  Thus, 
the  methane  is  obtained  by  breaking  down  the  more  complex  acetic  molecule; 
and  yet  further,  this  acetic  molecule  was  obtained  by  the  breaking  down  of  the 
more  complex  cellulose  molecule.  (Acetic  acid  is  produced  by  the  destructive 
distillation  of  wood.)  But  one  of  the  chief  aims  of  the  organic  chemist  is  to 
produce  organic  compounds  — the  more  complex  the  better  — from  their  con- 
stituents used  in  the  elementary  form,  that  is,  to  produce  organic  compounds  by 
the  employment  of  chemical  forces  alone  without  the  intervention  of  the  vital 
processes  of  animals  and  plants.  So  it  comes  about  that  chemists  have  made 
efforts  to  produce  marsh  gas  from  carbon  and  hydrogen.  The  effort  has  been 
successful,  and  it  is  the  more  interesting  because  methane  is  looked  upon  as  a 
sort  of  a fundamental  nucleus  of  organic  compounds. 

Ethane , or  ethyl  hydride , C2H6.  This  substance,  the  second 
hydrocarbon  of  the  paraffin  series,  is  ordinarily  a gas.  By  cold 
and  pressure,  however,  it  may  be  reduced  to  a liquid.  It  occa- 
sionally exists  in  nature  in  the  “ natural  gas  ” evolved  by  gas 
wells.  Ethane  also  exists  in  Pennsylvania  petroleum  dissolved 
in  the  liquid  hydrocarbons. 


PARAFFINS. 


43 


Ethane  may  be  produced  by  a number  of  different  methods. 
Theoretically,  one  of  the  most  interesting  is  that  whereby  it  is 
produced  from  methyl  iodide  and  zinc  in  a closed  glass  tube. 

2CH0I  Zn  = 2CH3  + Znl2 

The  action  shows  that  two  molecules  of  methyl  are  produced  ; 
but  as  a matter  of  fact,  when  the  experiment  is  performed,  the 
two  molecules  of  methyl  consolidate  to  form  one  of  ethane. 

2CH3  = C2H6 

Propane , or  propyl  hydride , C3H8.  This  substance  occurs  in 
petroleum.  It  is  a colorless  gas  of  no  considerable  practical 
importance. 

Butane , or  butyl  hydride , C4H10.  This  substance  is  a colorless 
gas.  Like  most  of  the  members  of  the  paraffin  series,  it  occurs 
in  petroleum.  It  may  be  produced,  however,  by  a variety  of 
chemical  reactions.  Like  the  foregoing  hydrocarbons,  also,  it  is 
capable  of  producing  a large  number  of  substitution  compounds. 
It  is  viewed  as  containing  a radicle,  butyl,  C4H9;  which  radicle, 
combining  with  halogens,  with  hydroxyl,  amidogen,  etc.,  gives 
rise  to  a set  of  compounds  corresponding  to  many  already 
described.  Thus,  it  forms  butyl  ethers,  butyl  alchohols,  butyl 
iodides,  butyl  esters,  butyric  acids,  butyl  amines. 

It  must  be  borne  in  mind,  however,  as  was  previously  stated, 
that  the  larger  number  of  carbon  atoms  in  butane  affords  oppor- 
tunity for  isomers. 

Normal  pentane , C5H12.  This  substance  is  a volatile  liquid.  It 
exists  in  petroleum.  It  is  produced  artificially  in  the  distillation 
of  cannel  coal  for  the  manufacture  of  illuminating  gas.  It  is 
assumed  that  pentane  contains  a hydrocarbon  radicle,  pentyl, 
C5Hn.  Like  members  of  preceding  groups,  it  affords  a large 
number  of  derivatives.  Of  course,  owing  to  its  number  of  atoms 
of  carbon,  it  forms  a larger  number  of  isomers  than  the  foregoing 
compound. 

Normal  hexane , C6H14.  This  is  also  a liquid.  It  exists,  like 
many  of  the  higher  hydrocarbons  of  this  series,  in  petroleum 
and  in  the  products  of  the  distillation  of  cannel  coal.  As  has 


44 


CARBON  COMPOUNDS. 


been  intimated  before,  there  are  five  possible  isomers,  all  of  which 
have  been  produced  and  studied.  Of  course,  they  give  rise  to 
various  alcohols  and  ethers,  acids,  and  other  derivatives,  also 
capable  of  forming  isomers. 

This  series  has  a great  many  members  with  higher  numbers  of 
carbon  atoms,  but  they  need  not  be  discussed  here. 

Fatty  Hydrocarbons  of  the  Olefine  Series,  CnH2n. 

The  olefines  form  an  important  natural  series  of  which  many 
members  are  known.  From  the  compound  having  C2  up  to  the 
compound  having  C30  the  list  of  known  compounds  is  nearly  com- 
plete. Below  are  the  names  and  formulas  of  a few  of  them  : 


Olefines,  CnH2n 


Ethylene, 

c2h4 

Octylene  (caprylene),  C8  H46 

Propylene, 

c3h6 

Nonylene, 

C9  h18 

Butylene, 

c4h8 

Dekylene, 

CioH2o 

Amylene  (pentylene),  C5H10 

Undekylene, 

ChH22 

Hexylene, 

c6h12 

Duodekylene, 

Ci2H24 

Heptylene, 

c7h14 

Tridekylene, 

Ci3H26 

Many  isomers  are  known. 

i.  They  all  have  this  structural  characteristic  (already  referred 

to)  viz.,  in  each  substance  is 

one  pair  of  carbon  atoms  held 

together  by  a 

double  bond  ; 

additional  carbon 

atoms,  if  any, 

being  held  by 

a single  bond. 

Thus  they  are  un 

saturated  com- 

pounds. 

2.  The  olefines  exist  in  certain  petroleums,  especially  that  of 
Russia  and  Burma  (only  in  small  quantity  in  American). 

The  olefines  are  produced  artificially  from  certain  other  carbon 
compounds — by  destructive  distillation,  for  example. 

3.  As  might  be  expected,  the  lower  members  of  the  series 
are  gases  at  ordinary  temperatures ; the  higher  members  are 
solids ; the  intermediate  members  are  liquids. 

4.  The  olefines  are  more  active  chemically  than  the  paraffins  ; 
a fact  due  to  the  double  linkage. 

One  important  feature  is  the  ease  with  which  they  take  on 
bromine  (and  indeed  other  chemical  substances),  thus  loosing  the 
double  bond. 

Of  course,  they  burn  with  luminous  flame. 


FATTY  HYDROCARBONS. 


45 


Ethylene , C2H4.  This  is  a colorless  gas.  It  is  produced  by  the 
dry  distillation  of  many  organic  substances,  as  in  the  manufacture 
of  illuminating  gas  from  cannel  coal — indeed,  it  is  a very  valuable 
constituent  of  the  gas,  because  it  affords  much  light. 

Ethylene  is  also  produced  when  sulphuric  acid  acts  upon  alco- 
hol. 

Ethylene  may  be  obtained  by  the  direct  combination  of  acety- 
lene, C2H2,  with  hydrogen,  under  the  influence  of  the  electric 
current. 

Ethylene  is  capable  of  affording  substitution  products  contain- 
ing chlorine  and  other  halogens.  It  affords  also  a very  large 
number  of  other  compounds  corresponding  in  a general  way  with 
the  organic  salts,  nitrogen  bases,  phosphorus  bases,  etc.,  already 
shown  to  be  produced  from  methane  and  ethane. 

Fatty  Hydrocarbons  of  the  Acetylene  Series,  CnH2n-2. 

Many  acetylenes  are  known. 

They  form  four  subordinate  series  of  which  two  are  worthy  of 
mention  here.  In  the  one  set  a given  molecule  having  three 
carbon  atoms  may  have  them  attached  by  one  bond  and  three 
bonds , as  in  the  first  allylene,  C3H4,  composed  as  follows, 
H3CC:CH.  In  the  other  set  there  may  be  two  bonds  and 
two  bonds , as  in  the  second  allylene,  C3H4,  composed  as  follows, 
H2C:C:CH2  . 

Acetylenes  are  known  from  the  member  having  C2  to  that 
having  C20  with  but  few  gaps  in  the  list. 

One  important  chemical  characteristic  of  the  one-three  acety- 
lenes is  their  tendency  to  combine  with  metallic  compounds, 
especially  those  of  copper  and  silver.  Thus,  the  first  acetylene, 
C2H2,  forms  copper  acetylene,  C2H2Cu20  and  silver  acetylene, 
C2H2Ag20,  both  of  which  are  explosive,  as  might  be  expected. 

Naturally  the  acetylenes  burn,  and  with  smoky  flame. 

The  first  member,  from  which  the  series  is  named,  is  itself 
called  acetylene. 

Acetylene , C2H2,  is  a colorless  gas  possessing  a peculiar  and 
disagreeable  odor. 

i.  It  exists  in  minute  quantity  in  illuminating  gas.  It  may 
be  produced  by  a variety  of  decompositions  of  organic  com- 


4 6 


CARBON  COMPOUNDS. 


pounds,  such  as  by  passing  vapors  of  methyl  alcohol,  ethyl  alco- 
hol, ethyl  ether,  etc.,  through  red  hot  tubes. 

2.  An  interesting  method  of  producing  acetylene  is  that  dis- 
covered by  Berthelot  and  already  referred  to  on  preceding  pages  ; 
that  is,  by  conveying  an  electric  current,  flowing  as  an  arc  from 
carbon  poles,  through  an  atmosphere  of  hydrogen.  (It  should  be 
observed  that  the  electric  spark  from  an  induction  coil  decom- 
poses acetylene.)  Under  the  prescribed  conditions,  the  carbon 
and  the  hydrogen  unite,  forming  acetylene.  This  process  has 
been  referred  to  before  as  the  first  step  in  many  organic  syn- 
theses. 

3.  Acetylene  may  be  readily  prepared  by  action  of  water  on 
calcium  carbide,  CaC2.  (The  calcium  carbide  is  formed  by  the 
action  of  an  arc  light  electric  current  on  a mixture  of  lime  or 
chalk  and  powdered  coal.) 

CaC2  ~1“  2H20  = Ca02H2  -j-  C2H2 

This  important  method  has  of  late  received  much  attention, 
for  it  is  believed  to  be  a cheap  process.  As  acetylene,  when 
burned  in  air,  affords  a very  brilliant  light,  it  is  thought  by  some 
that  the  process  under  discussion  may  have  important  commer- 
cial applications. 

Isoprene , C5H8,  is  a liquid  produced  by  decomposition  of  caout- 
chouc and  by  passing  vapor  of  turpentine,  C10H16,  through  a red 
hot  tube.  Isoprene  upon  exposure  to  light  changes  slowly  into 
a caoutchouc  similar  to  that  of  india  rubber.  If  this  process 
can  be  practically  applied,  it  may  become  of  great  importance  to 
the  rubber  industries. 


Fatty  Hydrocarbons  of  the  Valylene  Series,  C11H211-4. 

These  are  open  chain  compounds  with  a special  carbon  linkage. 
It  may  be  illustrated  by  the  constitution  of  the  first  compound 
known,  valylene,  C5H6,  whose  structure  is  believed  to  be  repre- 
sented by  the  expression,  H2C  : C(CH3) . C : CH  or  by  H3C  • CH  : 
CH  • C:CH. 

But  few  members  of  this  series  have  been  studied. 


FATTY  HYDROCARBONS. 


4 7 


Fatty  Hydrocarbons  of  the  Diacetylene  Series,  CnH2n-6. 

These  are  open  chain  compounds.  The  first  member,  diacety- 
lene, C4H2,  is  believed  to  have  the  constitution  expressed  by 
HC:C  * C ;CH. 

But  few  members  of  this  series  have  been  studied. 

This  last  fatty  series  must  be  carefully  distinguished  from  the 
important  aromatic  hydrocarbon  series , called  the  benzene  series, 
having  the  same  general  formula,  CnH2n_6. 


CHAPTER  VIII. 


FATTY  HYDROCARBONS. 


Petroleum,  Etc. 


Introduction.  Petroleum  flows  from  the  earth  as  a mixture  of 
oil,  gas,  salt  water,  and  sand.  When  it  subsides  in  a hollow,  the 
sand  and  water  fall  to  the  bottom,  the  gas  partly  escapes  into  the 
air,  while  the  oil  is  drawn  off  by  pipes  to  the  refinery. 

Chemical  Composition.  American  petroleum  consists  mainly  of 
hydrocarbons  of  the  paraffin  series,  CnH2n+2.  In  addition,  it  some- 
times has  olefines,  CnH2n,  and  occasionally  aromatic  hydrocar- 
bons, CnH2n_6.  In  some  cases  sulphur  compounds  are  present. 

Occurrence.  Petroleum  has  been  found  in  rocks  of  all  geolog- 
ical ages.  But  it  occurs  principally  in  those  of  the  Silurian  age — 
the  age  of  mollusks,  and  in  those  of  the  Devonian  age — the  age 
of  fishes.  Speaking  mechanically,  there  seem  to  be  necessary 
first,  an  original  source  of  oil ; above  this  a stratum  of  sand  which 
shall  hold  the  oil  as  in  a sponge ; above  this  an  impervious  stra- 
tum, as  of  shale  or  clay,  which  shall  act  as  a sort  of  cover  to  pre- 
vent the  escape  of  the  oil.  It  is  generally  admitted  that  the  oil 
ascends  from  below  into  the  sands  holding  it. 

Sources.  The  world’s  supply  of  petroleum  comes  principally 
from  the  United  States  and  Russia,  but  the  following  localities 
are  worthy  of  mention  : 


Austria,  Germany,  Italy;  Canada;  Japan;  Burma  and  India;  Peru,  the 
Argentine  Republic,  Equador. 

(The  oil  produced  by  the  distillation  of  bituminous  material,  in  Italy,  France 
and  elsewhere  should  not  be  confounded  with  that  derived  from  supplies  of  oil 
ready-formed  in  the  earth.) 

The  United  States  afford  about  f of  the  present  output  of  crude  oil ; Russia 
about  j ; Canada  and  Austria  about  ^ each. 


The  world’s  output  of  crude  oil,  per  annum  ( 
United  States,  about  . 

Russia,  “ 

Austria,  “ 

Canada,  “ 


n barrels  of  42  gals,  each) 
48,000,000  bbls. 
8,000,000  “ 

800.000  “ 

750.000  “ 


(48) 


PETROLEUM. 


49 


It  is  considered  not  improbable  that  the  region  about  the  Mackenzie  River 
may  prove  to  be  one  of  the  most  productive  areas. 

In  the  years  1894-5  there  has  been  a decided  decline  in  production  in  the  older 
fields  of  the  United  States  — accompanied,  however,  by  an  increase  in  the  case 
of  newer  fields. 


Petroletim  districts  of  the  United  States.  First,  the  Appa- 
lachian field  (embracing  western  Pennsylvania  and  New  York, 
West  Virginia,  and  eastern  Ohio.) 

This  is  at  present  the  one  furnishing  the  largest  amount  of  oil. 
Its  area  is  about  500  square  miles.  The  Pennsylvania  portion 
includes : (a)  the  Allegheny  districts,  (b)  the  Bradford  district, 

(c)  the  Warren  district  and  the  Forest  district,  (d)  the  Venango 
district ; this  has  proved  one  of  the  four  most  productive  coun- 
ties, perhaps  it  already  heads  the  list,  (e)  the  Butler  district, 
(f)  the  Beaver  district ; in  Beaver  County  a very  valuable  oil  has 
been  found,  different  in  quality,  and  generally  of  a higher  grade 
than  that  produced  elsewhere,  (g)  the  Washington  district.  The 
oils  of  these  districts  vary  considerably  in  their  consistency  and 
in  their  chemical  constitution,  but  they  do  not  yield  sulphur  oils 
as  some  of  the  other  fields  do. 

Second,  the  Limestone  field  (embracing  the  Lima  district  of 
western  Ohio  and  Indiana.)  This  affords  a dark-colored  and 
strongly  sulphuretted  oil.  It  commands  a relatively  lower  price, 
owing  to  the  expense  involved  in  the  removal  of  the  sulphur. 

Third,  the  Florence  field  of  Colorado.  Probably  the  yield  of 
oil  will  be  much  increased  in  the  future. 

Fourth,  the  Southern  California  field.  Here  also  there  are 
evidences  of  increased  production. 

Fifth,  the  Kentucky  field.  The  yield  has  been  thus  far  small, 
partly  on  account  of  the  cost  of  transportation  to  the  refinery. 

Sixth,  the  Wyoming  field.  The  oil  is  of  superior  quality  and 
capitalists  are  now  engaged  in  preparations  for  large  developments. 


Production  of  crude  petroleum  in  the  United  States  for  the  year  1894: 


Pennsylvania,  New  York,  and  West  Virginia,  about 
Ohio  and  Indiana,  about 

Colorado,  about  ..... 
California,  about  .... 

Kentucky  and  Tennessee,  about 
Wyoming  and  other  States,  about 


30.600.000  bbls. 

16.500.000  “ 

800.000  “ 

600.000  “ 

1,000  “ 

2,700  “ 


4 


48>503>7oo  “ 


CARBON  COMPOUNDS. 


50 


The  American  oil  deposits,  already  proved  by  boring,  are  said  to  represent  an 
area  of  over  200,000  square  miles. 

Oil  has  been  struck  at  from  50  to  100  feet  in  depth,  while  in  other  cases  it  has 
required  boring  to  1,000  feet,  or  even  to  3,000  feet. 

History  of  American  petroleum.  The  North  American  Indians 
appear  to  have  been  familiar  with  petroleum  oil  as  recognized  on 
the  surface  of  certain  pools.  At  first  this  oil  was  employed  in  a 
crude  condition  as  a medicinal  agent  under  the  name  of  Seneca 
oil.  In  certain  places,  the  whites  gathered  the  oil  by  saturating 
flannels  with  it,  later  wringing  out  the  oil  from  the  flannel. 

In  1833  Professor  Benjamin  Silliman,  Sr.,  in  an  article  in  the 
American  Journal  of  Science , describes  the  celebrated  oil  spring  of 
the  Seneca  Indians,  near  Cuba,  N.  Y.  He  says  “ they  collected 
petroleum  by  skimming  it  like  cream  from  the  milk  pan  ; ” he 
adds  that  “ the  oil  is  thick,  adhesive,  and  of  foul  appearance,  like 
very  dirty  tar  or  molasses,  but  that  it  is  purified  by  heating  it 
and  straining  it  while  hot  through  flannel  or  other  woolen  stuff.” 
Further  he  states  that  “the  people  in  the  vicinity  use  it  for 
sprains  and  rheumatism,  rubbing  it  upon  the  part  affected.” 
Apparently  the  petroleum  used  in  the  Eastern  States  under  the 
name  of  Seneca  oil  did  not  come  from  the  spring  described,  but 
from  a point  about  one  hundred  miles  from  Pittsburg  called  Oil 
Creek,  in  Venango  County. 

The  great  success  of  James  Young  and  others  in  making  oil  by  distillation 
from  bog-head  coal  and  from  shales,  in  Scotland,  led  to  an  attempt  to  make  oil 
from  similar  materials  in  the  United  States.  At  first  such  oil  was  distilled  from 
Albert  coal,  a kind  of  asphaltum  obtained  in  New  Brunswick.  A good  lubri- 
cating oil  was  made  in  this  way.  Later,  oils  were  manufactured  from  the  rich 
cannel  coals  of  Virginia  and  Kentucky.  In  the  neighborhood  of  the  year  1855 
oil  was  discovered  at  Tarentum,  not  far  from  Pittsburg,  by  men  who  were  bor- 
ing a well  for  salt  brine.  These  oils,  although  obtained  in  small  quantities, 
were  used  for  medical  purposes,  for  burning,  and  for  lubricating.  In  1854  a 
company  of  Eastern  gentlemen  became  interested  in  petroleum  and  one  of  them 
suggested  boring  as  a means  of  obtaining  oil  in  larger  quantities.  They 
engaged  Professor  Silliman  of  Yale  College  to  give  some  of  their  oil  a careful 
examination.  He  stated  that  in  his  opinion  “ it  contains  a large  proportion  of 
benzole  and  naphtha,  and  that  it  will  be  found  more  valuable  for  purposes  of 
application  to  the  arts  than  as  a medicinal,  burning,  or  lubricating  fluid.” 
Thereupon  the  company  secured  105  acres  of  land  near  the  junction  of  Pine  and 
Oil  Creeks,  and  they  engaged  the  notable  Col.  E.  L.  Drake  to  go  out  to  Titus- 
ville and  drill  an  artesian  well  for  oil.  Drake  appears  to  have  worked  through 
the  season  of  1858  and  a part  of  1859  under  many  difficulties;  but  in  August, 


PETROLEUM . 


51 


1859,  he  obtained  a small  amount  of  petroleum.  His  was  the  first  petroleum 
well  artificially  drilled.  Considerable  excitement  was  created  by  the  success  01 
this  well.  It  was  followed  by  the  permanent  development  of  a considerable 
territory  away  from  that  principal  centre.  Wells  were  bored  in  various  regions 
where  it  was  found  oil  could  not  be  obtained,  extending  along  the  Allegheny 
River,  and,  later,  into  Ohio  and  West  Virginia. 

In  i860  the  interest  in  Pennsylvania  over  the  finding  of  oil  was  intense.  It 
led  to  a period  of  excitement  surpassed  only  by  that  of  the  California  gold 
fever.  Pithole  City  in  1865  had  the  largest  post-office,  except  Philadelphia,  in 
Pennsylvania.  But  it  is  now  a place  of  no  consequence. 

During  the  first  two  years  of  success,  the  search  for  oil  was  restricted  to  the 
territory  around  Titusville ; later,  wells  were  struck  on  the  Allegheny  River 
with  abundant  success.  During  this  time  oil  was  pumped;  but  in  February, 
1861,  a flowing  well  was  struck  which  yielded  300  barrels  a day,  and  which  con- 
tinued to  flow  for  fifteen  months.  Before  the  surprise  and  interest  incidental 
to  this  discovery  had  expended  itself,  the  Phillips  well  was  struck,  yielding 
about  3,000  barrels  a day.  Other  wells  of  almost  equal  productiveness  were 
later  secured. 

Boring  the  wells.  The  oil  is  obtained  at  varying  depths.  Thus 
some  of  the  wells  of  West  Virginia  and  Ohio  are  only  60  or  80 
feet  deep,  while  some  of  those  in  Pennsylvania  (Washington 
County)  are  2,600  feet  deep.  It  is  frequently  the  case  that  new 
wells  yield  oil  without  pumping ; they  are  called  flowing  wells  or 
“ gushers.”  The  flow  seems  to  be  due  to  the  pressure  of  gas, 
which,  little  by  little,  escapes,  so  that  eventually,  all  wells  have  to 
be  pumped.  It  is  stated  that  the  average  production  of  above 
24,000  wells  actually  at  work  in  Pennsylvania  in  1886  was  a little 
short  of  three  barrels  per  day. 

Wells  are  drilled  in  the  United  States  by  the  use  of  extremely 
ingenious  appliances.  The  simplest  is  a heavy  chisel  attached  to  a 
long  rope.  By  means  of  a derrick  the  chisel  is  raised  and  dropped  ; 
from  time  to  time  the  tools  are  withdrawn,  a small  quantity  of 
water  is  poured  into  the  well,  then  a pump  is  applied  to  bring  to 
the  surface  pulverized  material  from  which  the  nature  of  the 
strata  attacked  may  be  determined.  Sometimes  when  a deep 
well  fails  to  yield  petroleum,  or  yields  but  little,  the  process 
called  “shooting”  is  employed.  A water-tight  torpedo  charged 
with  nitro-glycerine  is  lowered  into  the  well,  water  is  allowed  to 
fill  the  well,  then  the  torpedo  is  exploded  by  electricity  or  other- 
wise. As  a result  the  flow  of  oil  is  generally  increased. 

In  connection  with  petroleum  wells  some  curious  circumstances  may  be 
worthy  of  mention,  even  though  thought  incredible.  In  Venango  county, 


52 


CARBON  COMPOUNDS. 


Pennsylvania,  a well  called  “ the  Sunday  well,”  is  said  never  to  have  yielded  a 
crop  of  oil  except  on  the  first  day  of  the  week.  Another  curious  well  called 
“ the  lunatic  oil  spring,”  is  said  to  begin  to  flow  oil  when  the  new  moon  appears, 
increasing  in  volume  as  the  moon  grows.  When  the  moon  is  full  the  spring 
yields  about  three  barrels  of  oil  every  day,  the  yield  decreasing  and  increasing 
with  the  phases  of  the  moon. 

Transportation  of  oil.  The  early  method  of  transportation  of 
oil  was  by  the  use  of  barrels.  At  present,  oil  is  transported  not 
only  by  tank  cars,  but  also  by  6-inch  pipe  lines,  which  receive 
their  supply  of  oil  from  immense  tanks  near  the  wells.  The 
pipes  extend  to  Cleveland,  Chicago,  Philadelphia,  Brobklyn, 
Baltimore,  and  Buffalo,  aggregating  2,500  miles.  They  lie  but 
a short  distance  under  ground,  and  they  are  constantly  patrolled 
by  watchers  for  leaks  ; in  many  places  these  men  have  worn 
paths  miles  in  length,  so  that  it  is  very  easy  to  trace  the 
course  of  the  pipes.  In  connection  with  the  pipe  lines,  ingen- 
ious pumps  and  other  scientific  devices  are  used.  The  oil 
is  forced  along  steadily  over  hills  and  under  rivers  until  it  is 
delivered  at  the  proper  point.  Any  individual  owning  a well 
may  deliver  oil  at  tanks  near  by,  and  then  receive  at  once  a pipe 
line  certificate  for  the  proper  number  of  barrels  of  oil.  The  cer- 
tificates are  bought  and  sold  freely,  so  that  the  producer  of  the 
oil  virtually  receives  his  pay  at  once. 

Occasionally  tanks  have  been  struck  by  lightning  and  the  oil  set  on  fire.  In 
such  cases  the  oil  may  burn  at  the  top  for  a short  time  without  serious  damage ; 
the  unburned  oil  beneath  may  be  drawn  off  and  saved.  In  the  early  history  of 
tanks  a cannon  ball  was  sometimes  fired  at  the  lower  part  of  the  tank  so  as  to 
make  a hole  and  let  the  unburned  oil  run  into  a depression  of  the  earth  near  by, 
from  which  it  could  be  subsequently  recovered.  At  present  great  care  is  taken 
to  protect  tanks  by  lightning  rods,  as  well  as  by  safety  valves.  These  latter 
may  accommodate  the  expansion  of  the  oil  incidental  to  hot  weather. 

Illuminating  oil  may  be  shipped  in  tank  steamers  or  in  tin  cans.  Such  large 
numbers  of  cans  are  used  that  incidentally,  the  industry  of  their  manufacture 
is  a large  and  important  one. 

A singular  accident  is  narrated  as  having  occurred  in  Wisconsin  in  the 
night.  Some  cars  were  thrown  from  the  track;  two  of  them  contained 
naphtha,  and  the  liquid  spread  over  a marsh  near  by.  A boy  living  in  the 
vicinity  came  toward  the  wreck  with  an  open  lantern.  The  naphtha  became 
ignited,  the  cars  were  consumed,  one  of  the  railroad  men  was  burned  to  death, 
others  escaped  only  by  jumping  into  the  lake  near  by.  * 

Fractional  distillation  of  crude  oil.  As  the  oil  comes  from 
the  well  it  is  usually  mingled  with  salt  water.  After  standing 


PETROLEUM. 


53 


.awhile  the  salt  water  falls  to  the  bottom  of  the  mixture  and  may 
be  drawn  off.  Next  the  oil  goes  to  the  refinery.  There  it  is  at 
first  heated  in  large  kettles  practically  retorts ; the  oil  liber- 
ates vapor;  the  vapor  passes  through  condensers  and  forms 
gasolene  or  naphtha.  As  the  heating  proceeds,  oils  of  greater 
density  distil,  and  these  being  collected  in  other  reservoirs, 
are  used  for  the  manufacture  of  illuminating  oil.  By  and 
by,  heavier  oils  suitable  for  lubrication  are  obtained  ; these  oils 
are  often  spoken  of  as  paraffin  oils.  From  these  heavier  mate- 
rials also  the  substance  known  as  vaseline  is  produced. 

The  residuum  in  the  still  is  of  tarry  consistency  and  may  be 
used  mixed  with  fine  coal,  or  otherwise,  as  fuel. 

The  amount  of  illuminating  oil  obtained  is  increased  by  the 
process  called  “cracking.”  This  is  a form  of  destructive  distil- 
lation, rather  than  of  fractional  distillation.  A heavy  lubricating 
oil  when  dropped  into  a still  containing  heavy  oil  highly  heated 
becomes  itself  decomposed,  and  yields  vapors  of  illuminating  oil. 
Thus  the  fractional  distillation  of  Pennsylvania  petroleum  which 
ordinarily  gives  about  40  percent,  of  illuminating  oil  and  25  per 
cent,  of  lubricating  oil,  may,  by  the  process  of  cracking,  be  made 
to  yield  75  per  cent,  of  illuminating  oil  and  about  6 per  cent,  of 
lubricating  oil. 

In  obtaining  paraffin,  the  heavy  oil  from  the  still  is  cooled  by 
refrigerating  machines,  and  the  pasty  solid  is  subjected  to  the 
action  of  a hydraulic  press.  Later  the  paraffin  is  remelted  and 
filtered  through  bone  coal,  in  order  to  decolorize  it. 

Certain  of  the  distillates  from  the  heavier  portions  of  oil  are 
refined  by  filtration  and  otherwise,  and  then  form  a material 
known  as  vaseline. 

The  commercial  products  of  American  petroleum  may  be 
defined  chemically  as  follows  : The  light  group,  including  petro- 
leum ether,  etc. ; chiefly  pentane,  C5H12,  hexane,  C6H14(C6H12  also 
present),  heptane,  C7H16(C7H14  also  present). 

The  petroleum  spirit  group  ; chiefly  heptane,  octane,  nonane. 

The  burning  oil  group  ; chiefly  decane,  undecane,  dodecane. 

The  paraffin  wax  group  ; higher  hydrocarbons,  containing  from 
C20  to  C^. 


54 


CARBON  COMPOUNDS. 


The  following  are  a few  of  the  products  of  petroleum  : 

Cymogene.  It  boils  at  o C.  It  is  used  in  the  manufacture  of  artificial  ice. 

Rhigolene.  It  boils  at  i8x3^  degrees  C.  It  is  used  as  an  anasthetic. 

Petroleum  ether.  It  boils  at  from  70  to  90  degrees  C.  It  is  used  as  a solvent 
for  caoutchouc  and  also  in  gas  machines. 

Gasolene.  It  boils  at  70  to  90  degrees  C.  It  is  used  in  extracting  oil  from 
seeds  and  also  in  gas  machines. 

Naphtha.  It  boils  at  from  80  to  no  degrees  C.  It  is  used  in  vapor  stoves 
and  street  lamps.  It  is  also  employed  as  a solvent  for  resins. 

Ligroine.  It  boils  at  from  80  to  120  degrees  C.  It  is  used  for  burning  in 
sponge  lamps. 

Benzine.  It  boils  at  from  120  degrees  to  150  degrees  C.  It  is  used  as  a sub- 
stitute for  turpentine. 

Burning  oil  or  kerosene.  It  is  used  in  kerosene  lamps.  It  varies  as  to  fire 
test  from  no  degrees  Fahrenheit  to  150  degrees  Fahrenheit. 

Lubricating  oils.  These  oils  are  the  heavier  ones  as  found  in  nature,  or  else 
they  are  the  residue  from  the  fractional  distillation  of  crude  oils. 

Refining  burning  oil.  In  refining  illuminating  oil  the  portion 
of  the  distillate  suitable  for  this  purpose  is  placed  in  large  tanks 
and  agitated  with  ij  to  2 per  cent,  of  sulphuric  acid,  the  agitation 
being  accomplished  by  air  which  is  forced  into  the  tank.  When 
the  sulphuric  acid  has  done  its  work  the  mixture  is  allowed  to 
subside,  the  oil  coming  to  the  top.  This  is  drawn  off  and  washed 
with  water  and  a solution  of  sodium  carbonate,  the  latter  to 
remove  final  traces  of  acid.  The  acid  becomes  deeply  colored. 
It  is  charged  with  sulpho-compounds  of  the  olefines,  while  S02 
escapes.  The  sludge  acid  is  used  for  certain  inferior  purposes, 
for  example,  in  the  manufacture  of  fertilizers  (especially  for  acting 
on  insoluble  phosphates  with  a view  of  turning  them  into  the 
soluble  form.) 

In  refining  sulphur  oils  like  the  Lima  oils,  metallic  copper  or 
powdered  copper  oxide  or  a solution  of  lead  oxide  in  sodium 
hydroxide  is  often  employed,  the  intention  being,  of  course,  to 
withdraw  sulphur.  The  sulphur  oils  are  objectionable  because 
they  have  a very  offensive  odor. 

Russian  petroleum.  The  Russian  oils  come  from  two  districts, 
one  at  either  extremity  of  the  Caucasus  Mountains.  The  western 
district  is  on  the  Black  Sea,  near  the  Kouban  River.  The  east- 
ern district  is  on  the  Peninsula  of  Apsheron,  extending  into  the 
Caspian  Sea,  and  including  the  city  of  Baku. 

Although  the  existence  of  petroleum  (and  especially  the  gase- 
ous vapors  associated  with  it)  has  long  been  recognized  in  the 


PETROLEUM. 


55 


neighborhood  of  the  Caspian  Sea,  the  extensive  development  of 
the  Russian  petroleum  industry  has  been  since  about  i860.  Up 
to  1872,  petroleum  in  Russia  was  a State  monopoly.  At  the 
present  time,  about  one-half  of  the  petroleum  grounds  belong  to 
private  owners. 

The  extent  of  Russian  territory  in  the  Caucasus  capable  of 
yielding  oil  is  very  great.  Commencing  with  a point  on  the 
Taman  Peninsula  projecting  into  the  Black  Sea  on  its  northern 
boundary,  a line  drawn  on  the  map  in  a southeasterly  direction 
to  Baku  on  the  Caspian  Sea,  represents  a distance  of  about  1,500 
miles.  This  line  traverses  the  oil  belt.  Its  width  has  not  been 
accurately  determined,  but  if  ten  miles  is  taken  as  a minimum 
estimate,  the  area  represents  15,000  square  miles.  In  many 
parts  of  the  region  sketched,  ample  quantities  of  oil  have  been 
found. 

In  the  Baku  region,  the  oil  belt,  instead  of  being  ten  miles  in  width,  previ- 
ously assumed  as  an  average,  is  in  fact  about  200  miles  in  width.  This  district 
has  already  750  oil  wells  in  operation,  practically  all  of  these  yielding  without 
signs  of  exhaustion,  notwithstanding  the  fact  that  immense  loss  is  constantly 
caused  by  lack  of  experience  in  dealing  with  the  product.  Professor  Mende- 
leeff,  who  visited  Baku  in  1882,  declares  that,  all  things  considered,  these  oil 
wells  have  no  parallel  in  the  world,  and  that  the  general  district  referred  to  is 
not  only  more  productive  than  any  other  now  known,  but  it  is  also  more  exten- 
sive. 

The  chief  commercial  development,  however,  has  taken  place  in  the  region 
about  Baku.  This  has  been  largely  due  to  the  convenient  railroad  transportation 
to  Batoum,  on  the  Black  Sea,  from  which  point  the  principal  European  points 
are  easily  reached  by  water.  The  development  of  the  petroleum  trade  of  the 
Caucasus  is  largely  due  to  the  Nobel  Brothers.  They  started  business  at  Baku  in 
1874,  and  in  the  following  year  undertook  the  production  of  petroleum  on  a 
small  scale.  At  that  time  native  merchants  were  handling  oil  in  primitive 
ways,  using  carts  and  leather  bottles.  Overcoming  great  difficulties,  the  Nobel 
Brothers  brought  experts  from  the  United  States,  and  by  introducing  pipe 
lines,  storage  tanks,  tank  cars,  tank  boats,  they  soon  built  up  an  enormous 
business.  In  1887  the  Paris  house  of  Rothschilds  undertook  the  petroleum 
business  in  the  Caucasus  and  soon  surpassed  Nobel  Brothers. 

Next  to  the  Baku  region,  the  districts  of  Fer  and  Tiflis  are  worthy  of  mention. 
In  this  vicinity  oil  is  found  in  abundant  quantities,  and  it  has  been  used  for 
ages. 

The  Baku  wells  are  sufficiently  elevated  above  the  harbor  and  the  refineries  to 
allow  the  oil  to  reach  these  points  by  gravity.  About  400  wells  are  crowded 
together  in  this  neighborhood,  in  the  space  of  not  more  than  three  miles  square. 
The  deepest  well  yet  sunk  in  this  locality  is  only  about  825  feet,  while  oil  is 
often  reached  in  paying  quantities  at  a depth  of  100  feet. 


56 


CARBON  COMPOUNDS. 


The  Balakhany  field  is  about  eight  miles  from  the  town  of  Baku.  This 
district  covers  the  area  of  about  four  square  miles.  The  chief  source  of  oil  is 
the  Bibieibat  field,  which  is  about  three  miles  south  of  Baku. 

The  celebrated  Droojebah  well : When  oil  was  first  struck,  the  well  threw  out 
as  much  oil  in  one  day  as  nearly  the  whole  of  the  25,000  wells  in  America  put 
together.  The  oil  shot  up  to  a height' of  from  200  to  300  feet,  in  a stream  18 
inches  thick,  tearing  away  the  buildings  about  it,  and  producing  a roar  that 
could  be  heard  for  several  miles  around.  By  and  by  a lake  of  oil  was  produced 
which  ruined  everything  in  its  neighborhood  and  bankrupted  its  owners.  The 
well  flowed  at  the  rate  of  25,000  barrels  per  day  for  five  months  before  it  was 
possible  to  successfully  cap  and  control  it. 

In  1887  another  well,  yielding  oil  at  a depth  of  790  feet,  poured  out  a stream 
12  inches  in  diameter  to  a height  of  200  feet  for  69  days.  In  this  time  it  yielded 
3,000,000  barrels  of  oil,  of  which  one-third,  at  least,  was  lost,  owing  to  lack  of 
tank  capacity.  So  much  sand  was  thrown  up  that  one-story  buildings  fifteen 
feet  high,  within  100  yards  of  the  well,  were  buried  out  of  sight,  and  an  area  of 
ten  acres  around  the  well  was  covered  with  sand  to  a depth  of  from  one  to  fifteen 
feet.  Later  no  oil  at  all  could  be  obtained  from  the  well. 

Ordinarily  wells  do  not  continue  to  yield,  but  one  well  called  the  Kormilitza 
gave  nearly  800  barrels  per  day  for  twelve  years. 

Russian  methods  of  handling  oil.  In  the  Apsheron  Peninsula 
the  method  of  obtaining  oil  is  somewhat  different  from  that  pre- 
vailing in  the  United  States.  The  soil  being  very  soft,  the  boring 
is  usually  accomplished  by  rods  or  tubes,  rather  than  by  ropes. 
Often  the  first  tube  is  two  feet  in  diameter,  smaller  tubes  being 
used  as  the  operation  advances. 

The  wells  in  the  Baku  field  which  do  not  flow  cannot  be  pumped 
in  the  ordinary  manner,  because  of  the  large  amount  of  sand  in 
the  oil  (sometimes  as  great  as  30  or  40  per  cent.)  Generally  the 
oil  is  raised  to  the  surface  in  cylindrical  buckets  holding  about  a 
barrel  each. 

In  Russia  the  oil  is  allowed  to  flow  into  reservoirs  of  earth, 
where  the  sand  may  deposit ; later  the  oil  is  pumped  to  the 
refineries. 

The  Russian  petroleum  is  distributed  on  three  lines  : 

1.  On  the  Caspian  to  Astrakhan  and  thence  to  the  Volga 
River  and  the  interior  of  Russia. 

2.  On  the  Caspian  to  ports  opposite  Baku,  and  thence  to 
Central  Asia. 

3.  To  Batoum,  and  thence  to  western  Russia  and  to  the 
European  points. 


PETROLEUM. 


57 


The  various  companies  working  the  oil  wells  conduct  the  refin- 
eries, and  they  own  lines  of  transportation  in  bulk  by  sea,  and  in 
tank  cars  by  land.  They  also  have  large  shops  for  making  cars 
and  repairing  them.  They  maintain  also  large  numbers  of  cis- 
terns for  storage  of  the  various  products  on  the  shore. 

The  pipe  lines  at  Baku  are  of  wrought  iron,  cast  iron  offering 
too  much  resistance  to  the  flow  of  the  oil,  especially  in  the  winter. 

In  the  burning  of  residuum  from  Russian  petroleum  in  loco- 
motives and  steamers,  a method  similar  to  that  used  in  the 
United  States  is  followed.  The  oil  is  broken  into  minute  glob- 
ules by  means  of  a blast  of  steam.  In  this  form  it  burns  easily 
under  the  boilers.  Its  efficiency  is  about  double  that  of  an  equal 
weight  of  coal,  not  speaking  of  the  saving  in  labor  for  stoking, 
removing  ash,  etc. 

Toward  the  close  of  the  year  1893  majority  of  the  oil  producers  of  the 
Aspheron  peninsula  formed  a union  for  the  purpose  of  dealing  with  the  sale  of 
kerosene  oil  in  foreign  markets.  The  union  is  intended  to  continue  operations 
until  April,  1899.  The  general  plan  is  that  each  member  of  the  union  shall 
deliver  to  the  executive  committee  a determinate  quantity  of  kerosene  oil  of 
standard  quality,  and  then  the  committee  shall  have  full  power  to  distribute 
the  oil  in  foreign  countries  and  make  final  settlements  with  the  producers. 

Compariso7i  of  the  quality  of  Baku  crude  oil  with  American. 
Below  are  presented  a few  of  Mendeleeff’s  views  on  the  subject : 
apparently  they  are  rather  too  favorable  to  the  Russian  oil  : 

1.  The  American  petroleums,  speaking  generally,  consist  prin- 
cipally of  true  paraffins,  with  an  admixture  of  olefines  and  traces 
of  the  benzenes. 

The  Baku  oils  on  the  other  hand  are  to  a large  extent  made  up 
of  olefines  with  some  benzenes,  paraffins,  and  acetylenes.  They 
contain  little  or  no  solid  paraffins.  Such  differences  in  chemical 
constitution  might  be  expected  to  exert  a marked  influence  on 
the  quantity  and  quality  of  the  refined  products. 

2.  The  crude  Baku  oils  have  less  of  the  volatile  components, 
like  gasolene,  than  American  oils. 

3.  The  Baku  oil  may  yield  a larger  proportion  of  burning  oil 
than  does  American.  (Baku  about  40-50  per  cent,  by  weight 
from  crude.) 

4.  Baku  oil  is  said  to  yield  more  and  better  lubricating  oil 
than  American  does. 


53 


CARBON  COMPOUNDS. 


5.  Baku  crude  oil  can  be  distilled  without  leaving  carbonaceous 
residue.  But  this  is  not  by  any  means  fully  accomplished  in 
practice.  As  a matter  of  fact  the  Baku  oil  is  so  distilled  as  to 
yield  only  about  30  per  cent,  of  distillation  products  ; the  balance 
goes  into  “ astatki  ” or  so-called  “ refuse,”  which  is  used  merely 
as  fuel. 


Canada.  Petroleum  has  been  found  in  Quebec,  Nova  Scotia,  and  New 
Brunswick.  In  the  latter  territory  there  appears  to  be  an  immense  unexplored 
oil  region. 

The  chief  output  of  oil  has  been  from  the  township  of  Enniskillen,  in  the 
county  of  Lambton,  Ontario.  The  first  flowing  well  was  struck  in  February, 
1862,  and  before  October  of  the  same  year  there  were  no  less  than  35  wells. 

Burma.  In  Burma  there  are  at  least  600  wells,  but  the  richer  wells  show 
signs  of  exhaustion,  notwithstanding  the  fact  that  some  of  the  better  ones  have 
increased  in  production.  Burma  has  yielded  oil  in  increasing  quantities  from 
the  beginning  of  the  .century  until  1873.  Since  then  the  amount  obtained  has 
fluctuated.  Possibly  by  the  help  of  English  capital,  further  development  may 
take  place. 

East  Indies.  The  island  of  Sumatra  is  said  to  contain  a territory  available 
for  the  obtaining  of  petroleum  of  far  greater  extent  than  that  of  Russia. 
The  amount  of  product  is  at  present  moderate. 

Galicia.  In  Galicia  there  were  in  the  year  1S91,  199  establishments  engaged 
in  the  production  of  petroleum.  (There  were  also  79  ozokerite  mines.) 

Roumania.  In  Roumania  little  oil  has  been  obtained,  but  that  little  is  of 
excellent  quality.  The  reason  for  the  imperfect  development  of  the  business 
is  referable  partly  at  least  to  the  strict  laws  prevalent  with  respect  to  mining. 

Peru.  The  petroleum  beds  of  Peru  are  of  vast  extent.  Already  a moderate 
amount  of  oil  has  been  produced,  and  efforts  have  been  made  to  extend  the 
work  by  the  assistance  of  European  capital. 

Argentine.  In  the  Argentine  Republic  comparatively  little  has  been  done, 
though  the  field  seems  to  be  ample.  The  oil  produced  has  a local  sale,  for 
example,  it  is  used  on  locomotives  in  some  parts  of  the  State. 

Equador.  In  Equador  oil  is  known  to  exist,  but  it  has  been  but  little  worked. 

Petroleum  as  fuel.  Petroleum  appears  to  be  one  of  the  best 
forms  of  fuel,  being  concentrated  and  portable. 

1 pound  of  refined  petroleum  may  evaporate  12.2  pounds  of 
water. 

1 pound  of  crude  petroleum  may  evaporate  15  pounds  of  water. 
1 pound  of  poor  steam  coal  may  evaporate  6.5  pounds  of  water. 
1 pound  of  Pittsburg  coal  may  evaporate  7.2  pounds  of  water. 


PETROLEUM. 


59 


In  Russia  petroleum  is  used  for  locomotives  as  well  as  for 
steamers. 

Although  in  certain  places  petroleum  is  a more  costly  fuel  than 
coal,  a certain  increase  in  the  cost  of  coal  would  be  likely  to  alter 
these  relations. 

As  to  use  of  fuel  in  the  future,  it  appears  likely  that  for  the 
best  results,  fuel  should  be  changed  into  gas,  before  consumption, 
in  order  that  its  store  of  heat  energy  may  be  developed  most 
economically.  Petroleum  has  the  advantage  of  lending  itself 
most  easily  and  completely  to  this  treatment. 

The  increased  use  of  crude  petroleum  for  fuel  is  noticeable 
when  it  is  stated  that  of  about  35,000,000  barrels  produced  in  the 
United  States  in  1889,  over  12,000,000  barrels  were  used  for  fuel, 
generally  in  place  of  coal. 

Theories  of  the  origin  of  petroleum.  No  theory  of  the  origin  of 
petroleum  has  yet  gained  general  acceptance. 

First  theory  : It  is  believed  by  some  that  petroleum  was  pro- 
duced in  the  earth  by  a kind  of  distillation  process  from  the 
remains  of  marine  or  other  plants.  If  this  process  had  indeed 
been  carried  on,  itjwould  be  expected  that  along  with  the  petro- 
leum would  be  found  materials  resembling  charcoal  or  coke.  But 
these  are  not  so  observed. 

Again,  in  accordance  with  this  theory,  it  would  be  expected 
that  petroleum  would  be  closely  associated  with  coal  pits,  but 
such  association  seldom  occurs. 

Second  theory : Many  scientists  believe  that  petroleum  has 
been  formed  from  animal  deposits.  In  accordance  with*  this 
theory,  large  collections  of  animal  matters,  for  example,  remains 
of  mollusks  and  fishes,  have  undergone  decomposition  by  reason 
of  heat  and  pressure.  Whatever  difficulties  may  be  found  in  this 
theory,  it  must  be  admitted  that  in  many  parts  of  the  globe, 
immense  phosphoric  deposits  occur  which  are  plainly  referable 
to  the  bones  of  animals.  Further,  immense  limestone  deposits 
underlie  the  petroleum  sands.  Again,  recent  experiments  have 
shown  that  certain  animal  fats,  such  as  fish  oils,  when  heated  in 
dosed  vessels  under  high  pressure,  yield  large  quantities  of 
hydrocarbons  corresponding  to  those  found  in  petroleum.  This 
shows  that  the  transformation  referred  to  is  not  an  impossible 
one. 


6o 


CARBON  COMPOUNDS. 


Third  theory : Some  scientists  have  proposed  the  idea  that 
petroleum  has  been  formed  and  perhaps  is  now  in  process  of 
formation  from  inorganic  materials.  Thus  Sokoloff  suggests  that 
during  the  creation  of  this  planet,  the  hydrocarbons  formed  in 
the  period  of  original  atomic  union  gathered  gradually  so  as  to 
produce  the  petroleum  deposits. 

Fourth  theory:  The  Russian  chemist,  Mendeleeff,  believes 
that  petroleum  is  formed  by  the  action  of  water  at  high  tempera- 
tures and  pressures  on  carbide  of  iron  existing  in  the  earth’s 
crust.  In  this  view,  the  fissures  caused  by  the  upheaval  of 
mountain  chains  permit  water  to  reach  heated  carbide  of  iron. 
Thereupon  the  iron  combines  with  the  oxygen  of  the  water,  pro- 
ducing iron  ores ; and  the  carbon  combines  with  the  hydrogen 
of  the  water,  producing  the  hydrocarbons  of  petroleum.  After 
their  formation,  these  hydrocarbons  pass  up  as  vapor  until  they 
reach  sedimentary  strata  cool  enough  to  condense  them.  The 
occurrence  of  petroleum  in  active  volcanic  areas,  as  in  Sicily  and 
Japan,  seems  to  accord  with  this  theory.  The  theory  receives 
support  also  from  the  fact  that  petroleum  is  usually  found  in  the 
vicinity  of  mountains.  An  attractive  feature  of  this  hypothesis 
is  that  it  assumes  that  petroleum  is  still  forming  beneath  the 
surface  of  the  earth  and  that  the  supply  may  be  therefore  looked 
upon  as  in  a sense  inexhaustible.  Ingenious  as  this  theory  is, 
it  is  subject  to  many  objections. 

Some  scientists  have  endeavored  to  make  a combination  of 
theories,  with  the  notion  that  different  petroleum  deposits  may 
have  been  produced  differently,  some  by  one  chemical  process, 
some  by  another. 

4ft 

Natural  Gas. 


This  substance  is  obtained  notably  in  Pittsburg  and  its  neigh- 
borhood, when  borings  to  depths  varying  from  500  to  2,000  feet 
strike  the  pockets  containing  it.  At  first  it  issues  at  a pressure 
estimated  at  about  1,000  lbs.  per  square  inch — but  this  rapidly 
diminishes.  (The  neighborhood  of  Pittsburg  has  above  100 
wells.) 


PETROLEUM . 


6l 


The  average  composition  of  natural  gas  is : 


Marsh  gas,  CH4, 
Hydrogen, 

Nitrogen,  . 

Ethane,  C2H6,  . 
Ethylene,  C2H4, 

Carbon  dioxide,  C02, 
Carbon  monoxide,  CO, 
Oxygen,  . 


60.  to  80.  per  cent,  by  volume. 
5.  “ 20. 


1.  “ 12. 


8, 


o. 


2. 


3.  “ 2. 

trace  “ trace, 
trace  “ trace. 


The  use  of  natural  gas  as  a fuel  has  attained  large  proportions 
in  the  neighborhood  of  Pittsburg.  It  has  replaced  millions  of 
tons  of  coal. 


Asphaltum. 


Asphaltum,  albertite,  maltha,  are  names  applied  to  semi-solid 
bituminous  substances  found  in  the  earth.  They  vary  very  much 
in  composition  and  purity.  In  general,  they  are  mixtures  of 
hydrocarbons,  apparently  of  the  fatty  series.  They  are  largely 
used  mixed  with  sand,  limestone,  or  other  mineral  matters,  for 
street  pavements.  Certain  kinds  of  asphaltum  are  very  valuable 
for  waterproofing  and  electrical  insulating  purposes. 


Ozocerite,  or  Ozokerite. 


This  is  a natural  mineral  wax,  somewhat  similar  to  paraffin, 
but  composed  of  CnH2n.  It  has  of  late  been  found  to  some 
extent  in  Utah.  Previously,  practically  its  only  source  was 
Galicia,  in  Austria.  With  a moderate  amount  of  refining,  it 
becomes  white.  It  is  a valuable  substitute  for  beeswax.  It  has 
been  considerably  used  for  electrical  insulating  purposes. 


CHAPTER  IX. 


HALOGEN  DERIVATIVES  OF  FATTY  HYDRO- 
CARBONS. 

These  are  compounds  produced  by  substituting  one  or  more 
atoms  of  fluorine,  chlorine,  bromine,  or  iodine,  alone  or  in  com- 
bination, for  hydrogen  atoms  in  hydrocarbons.  Hundreds  of 
such  compounds  are  known  and  have  been  studied.  But  only  a 
few  have  obtained  industrial  importance. 

The  following  table  gives  a few  of  such  compounds  to  suggest 
the  kind  of  displacements  possible  : 

Synopsis  of  Methane  Derivatives. 

Methane,  marsh  gas,  CH4. 


Halogen  substitution  compounds : 


CH3C1 

CH3Br 

ch3i 

Methyl  chloride 

— bromide 

— iodide 

CH2CI2 

CH2Br3 

ch2i2 

Methylene  chloride 

— bromide 

— iodide 

CHCI3 

CHBr2 

chi3 

Chloroform 

Bromoform 

Iodoform 

CC14 

CBr4 

ci4 

Carbon  tetrachloride 

— tetrabromide 

— tetraiodide 

The  following  compounds  of  this  class  are  worthy  of  special 
mention  here  : 

Methyl  chloride , CH3C1.  This  substance  is  a colorless  gas 
which  easily  condenses  to  the  liquid  form  and  easily  volatilizes 
again.  It  is  prepared  to  a considerable  extent  for  use  in  the  arts. 
In  the  manufacture  of  aniline  colors,  it  is  employed  as  a means  of 
introducing  methyl  into  compounds  in  which  it  is  desired. 

It  is  also  employed  in  the  production  of  artificial  cold. 

(62) 


HALOGEN  DERIVATIVES . 


63 


Chloroform , CHC13.  This  substance  is  important  when  con- 
sidered both  from  the  theoretical  and  from  the  practical  side.  It 
may  be  produced  by  the  action  of  chlorine  gas  on  marsh  gas. 

It  is  not  easily  produced  at  present  from  methyl  alcohol. 

It  is  ordinarily  manufactured  by  the  action  of  bleaching  pow- 
der upon  ethyl  alcohol. 

Chloroform  is  largely  used  in  surgery  and  medicine  for  produc- 
ing insensibility  to  pain.  While  it  is  of  untold  value  for  such 
purposes,  it  must  not  be  forgotten  that  death  has  often  ensued 
from  an  overdose.  Ethel  ether,  commonly  called  sulphuric  ether, 
is  considered  a safer  anaesthetic. 

Iodoform , CHI3,  and  bromoform , CHBr3,  correspond  in  struc- 
ture with  chloroform.  The  former  is  largely  used  in  surgery. 


CHAPTER  X. 


ALCOHOLS. 

Of  the  Fatty  Series. 

The  word  alcohol  was  originally  applied  to  the  principal  sub- 
stance generated  by  the  fermentation  of  grape  juice,  viz.,  that 
substance  now  known  as  ethyl  alcohol,  C2H5’OH.  The  word  has 
since  been  extended  so  as  to  include  a class  of  substances.  All 
members  of  this  group  contain  one  or  more  molecules  of  the  radi- 
cle hydroxyl,  OH. 

Alcohols  are  classified  in  two  ways  : 

First.  By  the  number  of  hydroxyl  groups  (OH). 

A monohydric  alcohol  has  one  hydroxyl  group. 

Example:  Ethyl  alcohol,  C2H5OH 

A dihydric  alcohol  has  two  hydroxyl  groups. 

Example : Ethylene  alcohol,  C2H4(OH)2 


A trihydric  alcohol  has  three  hydroxyl  groups. 

Example:  Propenyl  alcohol,  C3H5(OH)3,  (glycerol  or  glycerine) 


A monohydric 
alcohol 
CH3 

I 

CH2 

ch2oh 

Propyl  alcohol 


A dihydric 
alcohol 
CH3 

CHOH 

I 

ch2oh 

Propylene  alcohol 


A trihydric 
alcohol 
CH2OH 

HOH 

CH2OH 

Propenyl  alcohol 


Second.  By  the  position  of  the  hydroxyl  group. 

K primary  alcohol  contains  the  group  CH2OH.  It  has  the  hydroxyl  group 
attached  to  an  atom  of  carbon  which  is  attached  to  not  more  than  one  other 
carbon  atom. 

Examples:  Primary  butyl  alcohol,  CH3*CH2CH*CH2‘OH 


Primary  isobutyl  alcohol,  : CH4CH2OH 

(64) 


ALCOHOLS. 


65 


In  a primary  alcohol  the  hydrogen  in  a methyl  residue,  CH3,  is  replaced  by 
hydroxyl. 

Primary  alcohols,  when  oxidized,  yield  progressively  aldehydes  and  organic 
acids  containing  respectively  the  original  number  of  carbon  atoms.  Thus, 
ethyl  alcohol,  C2H5OH,  by  oxidation,  forms  first,  aldehyde,  C2H4O,  or 
CH3*COH,  and  then,  by  further  oxidation,  acetic  acid,  C2H4O2,  or  CH3COOH. 

A secondary  alcohol  contains  the  group  CHOH.  It  has  the  hydroxyl  group 
attached  to  an  atom  of  carbon  which  is  attached  to  two  other  carbon  atoms. 

Example : Secondary  butyl  alcohol,  CH3-CH2*CHOH*CH3 

In  a secondary  alcohol  the  hydrogen  in  a methylene  residue,  CH2,  is  replaced 
by  hydroxyl. 

Secondary  alcohols,  when  oxidized,  yield  progressively  ketones  containing 
the  original  number  of  carbon  atoms,  and  then  organic  acids  containing  a 
smaller  number  of  carbon  atoms.  Thus,  secondary  propyl  alcohol,  C3H7OH, 
or  CH3*CHOH*CH3,  by  oxidation,  forms  first,  a ketone  called  dimethyl  ketone 
or  acetone,  C3H60,  or  CH3*COCH3;  and  then,  by  further  oxidation,  more 
than  one  acid  having  fewer  carbon  atoms. 

A tertiary  alcohol  contains  the  group  COH.  It  has  the  hydroxyl  group 
attached  to  an  atom  of  carbon  which  is  attached  to  three  other  carbon  atoms. 

Example : Tertiary  isobutyl  alcohol,  : COH*CH3 

In  a tertiary  alcohol  the  hydrogen  in  a methenyl  residue,  CH,  is  replaced  by 
hydroxyl. 

Tertiary  alcohols,  when  oxidized,  do  not  yield  aldehydes  nor  ketones  nor  cor- 
responding acids.  They  yield,  however,  two  non-corresponding  acids  having 
an  amount  of  carbon  lower  than  that  of  the  original  alcohol.  The  lowest  alco- 
hol of  this  class  is  tertiary  butyl  alcohol,  C4H9OH,  or  (CH3)3COH. 

Butane,  C4H10,  is  the  lowest  paraffin  compound  forming  all  three  : primary, 
secondary,  and  tertiary  alcohols.  They  all  have  the  empirical  formula,  C4H10O. 


I.  Alcohols  with  One  Atom  of  Oxygen. 

These  constitute  an  important  group.  A large  number  of 
members  are  known.  Commercially  the  most  important  are 
methyl  alcohol  and  ethyl  alcohol. 

The  following  list  refers  to  about  eighty  monohydric  alcohols 
now  known  ; only  a few  are  expressed  in  detail. 

It  will  be  seen  that  those  having  the  smaller  number  of  atoms 
are  inclined  to  be  liquid  at  ordinary  temperature ; as  the  numbers 
of  atoms  in  the  molecule  increase,  the  tendency  toward  solidity 
5 


66 


CARBON  COMPOUNDS. 


increases.  The  comparatively  regular  advances  in  boiling  points 
and  melting  points  are  very  significant.  They  represent  a funda- 
mental tendency  which  pervades  the  field  of  organic  chemistry. 

Fatty  Alcohols— Monohydric. 


Boiling 

or  Empirical 

melting 

point,  formula. 

Degrees  C. 


I. 

Methyl  alcohol, 

boils, 

67. 

c h4o 

ch3-oh 

2. 

Ethyl  “ 

“ 

78.4 

c2h6o 

CH3-CHoOH 

3* 

Propyl  “ 

“ 

97*4 

c3h8o 

ch3-ch2.ch2-oh 

CH3-CH(OH)-CH3 

4- 

Butyl  “ 

IJ7* 

C4H10O 

CH3-(CH2)2-CH2.OH 

CH3-CH(OH-CH2.CH3 

(CH3)2-CH.CH2-OH 

(CH3)2-C(OH)-CH3 

5- 

Amyl  “ 

< 1 

i37* 

c5H12o 

eight  forms  known. 

6. 

Hexyl  “ 

“ 

i57- 

c6h14o 

fourteen  “ “ 

7- 

Heptyl  “ 

“ 

175-5 

c7h16o 

thirteen  “ “ 

8. 

Octyl  “ 

“ 

195-5 

c8h18o 

nine  “ “ 

9- 

Nonyl  “ 

melts, 

— 5- 

c9h20o 

six  “ “ 

IO. 

Dekyl  “ 

« < 

7- 

CioH220 

five  “ “ 

ii. 

Hendekatyl  “ 

ChH240 

two  “ “ 

12. 

Dodekyl  “ 

24. 

Ci2H260 

two  “ “ 

13- 

Dihexyl  carbinol, 

“ 

42. 

CibHosO 

one  form  “ 

r4. 

Tetradekyl  alcohol, 

Ci4H30O 

two  forms  “ 

!5- 

Cetyl  “ 

“ 

49. 

Ci6H340 

one  form  “ 

16. 

Oktadekyl  “ 

“ 

59- 

Ci8H380 

one  “ “ 

i7- 

Medicagol, 

“ 

80. 

C2oH420 

one  “ “ 

18. 

Dilauryl  alcohol, 

“ 

75- 

C23H480 

one  “ “ 

19. 

(A  primary  alcohol), 

c25h52o 

one  “ “ 

20. 

Ceryl  alcohol, 

“ 

79- 

c27h58o 

three  forms  “ 

21. 

Myricyl  “ 

<< 

85. 

C3oH620 

one  form  “ 

22. 

Dipalmityl  carbinol, 

“ 

85. 

C3iH640 

one  “ “ 

23- 

Tarchonyl  alcohol, 

“ 

82. 

C50H102O 

(?)  one  “ “ 

Methyl  alcohol , commonly  called  wood  spirit,  CH3OH.  This 
substance  is  a colorless  volatile  liquid  resembling  in  some  ways 
ordinary  or  ethyl  alcohol.  It  strictly  resembles  the  latter  in  its 
plan  of  molecular  structure. 


ALCOHOLS. 


6; 


Methyl  alcohol  is  ordinarily  produced  by  the  destructive  distil- 
lation of  wood.  Wood  is  placed  in  a retort,  usually  of  iron. 
Upon  heat  being  applied  to  the  retort,  the  wood  undergoes  decom- 
position. Vapors  of  various  kinds  are  driven  off,  and  when  they 
are  condensed  in  the  receiver  provided,  they  are  found  to  contain 
a great  many  different  substances.  Among  them  are  water, 
methyl  alcohol,  acetic  acid,  tarry  matters.  This  impure  mass 
may  be  redistilled  with  sodium  hydroxide,  whereupon  a purer 
methyl  alcohol  is  obtained. 

Methyl  alcohol  and  certain  other  methyl  compounds  are  now  produced  as  a 
by-product  by  proper  treatment  of  certain  residues  of  the  beet-sugar  industry. 
The  materials  known  as  vinasses  were  formerly  thrown  away.  They  are  now, 
however,  subjected  to  a destructive  distillation  whereby  methyl  compounds  are 
produced  in  the  distillate  and  certain  potassium  salts  are  obtained  in  the  dry 
residue. 

Methyl  alcohol  is  used  to  some  extent  as  a substitute  for  ethyl 
alcohol.  In  most  commercial  nations  there  prevails  the  policy  of 
securing  a large  revenue  by  a tax  upon  articles  considered  injuri- 
ous. With  this  principle  in  view,  liquids  containing  ethyl  alcohol 
are  heavily  taxed.  The  tax,  however,  bears  not  only  upon  that 
alcohol  which  is  intended  to  be  or  may  be  used  for  drinking  pur- 
poses, but  also  upon  such  as  is  used  as  a solvent  for  gums  or 
resins  in  the  arts.  In  order  to  relieve  manufacturers  from  this 
impost,  the  English  government  liberates  from  taxation  what  is 
called  methylated  spirit ; that  is,  mixtures  of  90  per  cent,  ethyl 
alcohol  and  10  per  cent,  methyl  alcohol.  This  regulation  is  based 
upon  the  theory  that  the  methylated  spirit  cannot  be  used  for 
drinking  on  account  of  the  offensive  flavor  imparted  by  the 
methyl  alcohol,  but  that  the  latter  does  not  unduly  reduce  the 
solvent  power  of  the  ethyl  alcohol. 

Synopsis  of  Inorganic  Synthesis  of  Methyl  Alcohol. 

1.  Produce  marsh  gas,  CH4.  Submit  sulphuretted  hydrogen  to  the  action  of 
carbon  disulphide  in  presence  of  copper. 

2.  Produce  methyl  chloride,  CH3C1.  Submit  marsh  gas  to  chlorine  gas  in 
diffused  sunlight. 

CH4  -h  Cl2  = CH3CI  -f  HC1. 

3.  Produce  methyl  alcohol.  Submit  methyl  chloride  to  the  action  of  potas- 
sium hydroxide. 

CH3CI  + KOH  = CH3OH  + KC1. 


68 


CARBON  COMPOUNDS. 


Ethyl  alcohol , C2H5OH.  Ethyl  alcohol  is  looked  upon  as  cor- 
responding to  substances  like  potassium  hydroxide,  KOH. 

The  substance  was  recognized  in  the  very  ancient  times  as 
formed  in  certain  processes  of  fermentation,  particularly  the 
fermentation  of  wine.  Many  different  kinds  of  fermentation 
have  been  recognized  ; this  particular  kind  has,  therefore,  been 
specially  designated  as  the  vinous  fermentation.  The  juice  of  the 
grape,  like  that  of  many  other  fruits,  contains  a variety  of  sub- 
stances. Among  them  may  be  mentioned  sugar,  water,  and  cer- 
tain albuminous  matters.  Such  liquids  often  set  up  fermentation 
— apparently,  though  not  really,  of  themselves.  Sometimes  the 
operation  is  initiated  or  else  hastened  by  the  addition  of  yeast. 
The  fermentation,  once  started,  proceeds  for  a considerable  time. 
The  principal  change  is  now  known  to  be  due  to  the  sugar 
present,  the  amount  of  alcohol  formed  depending  strictly  on  the 
amount  of  sugar  that  undergoes  metamorphosis.  Further,  it  is 
noted  that  the  metamorphosis  is  strictly  dependent  upon  the 
presence  of  minute  organisms  in  the  juice.  These  organisms, 
called  ferments,  are  vegetable  in  nature.  If  by  any  means,  all 
the  organisms  in  a portion  of  fruit  juice  are  destroyed,  fermenta- 
tion does  not  proceed  until  others  have  been  introduced  either 
from  the  air  or  in  what  is  called  yeast.  It  is  worthy  of  note, 
also,  that  the  albuminous  matters  favor  the  process.  They  seem 
to  act  as  a sort  of  pabulum  for  the  microscopic  plant  which  car- 
ries on  fermentation.  When  fermentation  has  proceeded  to  a 
certain  extent,  the  alcoholic  product  stops  the  process  by  some- 
how interfering  with  the  vital  processes  of  the  microscopic  plant. 


Under  certain  circumstances,  fruit  juices  like  wine  and  cider  are  capable  of  a 
further  fermentation  called  souring,  or  the  acetous  fermentation;  in  such  case 
that  alcohol  produced  in  the  vinous  fermentation  is  changed  into  acetic  acid. 

In  the  change  from  sugar  to  alcohol,  carbon  dioxide  is  evolved.  This  mani- 
fests itself  in  the  froth  of  malt  liquors  like  ale,  and  in  the  gas  that  escapes  from 
certain  sparkling  wines  like  champagne. 

But  ethyl  alcohol  and  carbon  dioxide  are  by  no  means  the  only  substances 
produced  during  vinous  fermentation.  Certain  organic  acids  and  organic  ethers 
are  formed,  their  character  and  amount  depending  on  the  nature  of  the  original 
fruit  from  which  the  sugary  juice  was  obtained.  These  ethers  impart  flavor  to 
the  beverage  formed.  They  do  the  same  in  the  case  of  distilled  spirits  after- 
wards manufactured  from  the  fermented  wine. 


ALCOHOLS . 


69 


For  the  preparation  of  ethyl  alcohol,  then,  ordinarily  some 
sugary  substance  is  fermented.  The  next  important  step  is  dis- 
tillation. The  fermented  liquor,  being  introduced  into  a suitable 
retort,  commonly  called  a still,  is  heated  ; the  operation  being 
performed  with  the  greatest  care.  From  the  liquor  the  alcohol 
is  expelled  as  vapor  ; as  such  it  passes  over  into  the  condenser, 
and  there  returns  to  the  liquid  state.  Some  water  vapor  goes 
over  with  it,  and  some  alcohol  remains  in  the  still ; for  water  and 
alcohol  have  so  great  an  affinity  for  each  other  that  it  is  almost 
impossible  to  separate  them  perfectly. 

The  ordinary  strong  alcohol  of  commerce  is  called  ninety-five  per  cent,  alco- 
hol; that  is,  it  contains  in  the  neighborhood  of  five  per  cent,  of  water.  In 
some  cases,  the  water  may  be  largely — but  not  entirely — removed  by  distilling 
the  ninety-five  per  cent,  alcohol  with  quicklime  or  potassium  carbonate,  or 
some  other  substance  having  a strong  affinity  for  water.  The  alcohol  vapor 
when  condensed  in  a suitable  receiver  affords  what  is  called  absolute  alcohol. 

For  some  purposes,  in  the  arts,  weaker  alcohol  may  be  used.  That  called 
proof  spirit  contains  about  fifty  per  cent,  by  weight  of  alcohol.  Reference  has 
already  been  made  (see  page  67)  to  methylated  spirit,  a mixture  of  ninety  per 
cent,  ethyl  alcohol  and  ten  per  cent,  methyl  alcohol. 

The  ordinary  method  for  producing  alcohol  has  been  detailed. 
There  are  many  other  methods  of  obtaining  the  substance  by  the 
proper  reaction  of  ethyl  compounds.  These  latter,  however,  have 
a theoretical  interest  rather  than  a practical  one.  One  process  is 
given  below.  Stated  in  full,  it  shows  how,  by  organic  synthesis, 
ethyl  alcohol  may  be  produced  from  the  lifeless  elements  com- 
posing it  without  the  intervention  of  the  processes  of  living  ani- 
mals or  plants. 

Inorganic  Synthesis  of  Ethyl  Alcohol. 

1.  Prepare  acetylene,  C2H2,  by  running  the  electric  current  from  carbon 
poles  through  an  atmosphere  of  hydrogen. 


C2  + H2  = C2H2 


2.  Prepare  ethylene,  C2H4,  by  uniting  acetylene  with  hydrogen  by  the  aid 
of  platinum  black. 


c2h2  + h2  = c2h 


4 


3.  Prepare  hydrogen  ethyl  sulphate,  HC^HsSCh,  by  passing  ethylene 
through  concentrated  sulphuric  acid. 


c2h4  + h2so4  = HC2H5S04 


70 


CARBON  COMPOUNDS. 


4.  Prepare  ethyl  alcohol  by  heating  ethyl  sulphuric  acid  with  potassium 
hydroxide. 

HC2H5S04  + 2KOH  = C2H5OH  + h2o  + k2so4 

Uses  of  ethyl  alcohol.  The  enormous  consumption  of  alcoholic 
beverages,  as  shown  by  statistics,  cannot  escape  observation. 
While  ethyl  alcohol  is  considered  by  physicians  as  a most  valuable 
stimulant  when  properly  used,  the  results  of  the  improper  use  of 
alcoholic  liquids  are,  as  every  one  must  see,  most  lamentable. 

Alcohol  has  a large  number  of  important  uses  in  science  and 
in  the  arts.  Enormous  quanties  are  used  in  museums  for  the 
preservation  of  natural  history  specimens. 

In  the  chemical  laboratory  large  quantities  are  used  in  inorganic 
work  as  a special  solvent,  in  organic  work  both  as  a solvent  and  as 
a source  of  the  radicle  ethyl  to  be  transferred  or  transformed  into 
other  compounds.  It  is  certainly  one  of  the  main  reagents  of  the 
organic  laboratory. 

Alcohol  is  used  in  a variety  of  arts. 

Thus  it  is  used  as  a fuel  by  jewelers  in  blowpipe  lamps,  as  a solve?it  in  the 
preparation  of  transparent  soap,  in  the  securing  of  alkaloids,  etc.,  from  vege- 
table products,  in  the  blending  of  essential  oils  in  perfumery,  in  the  prepara- 
tion of  gums  and  resins  for  varnish  and  enamel,  and  for  the  stiffening  of  felt 
hats,  also  in  the  preparation  of  collodion,  as  a special  source  of  ethyl  in  the 
manufacture  of  artificial  fruit  extracts  and  flavoring  compounds,  and  in  the 
preparation  of  fulminates  for  use  in  ammunition. 


Alcoholic  Liquors. 

Alcoholic  liquors  are  usually  divided  into  three  groups  : malt 
liquors,  wines,  and  spirits. 

In  the  preparation  of  beer  and  similar  malt  liquors , barley  is  the 
grain  chiefly  used. 

1.  The  first  step  is  the  germination  of  the  grain  or  sprouting. 
By  this  process  the  starch  is  altered  into  dextrin  and  glucose. 
When  the  sprouting  has  advanced  sufficiently  it  is  checked  by 
heating  and  drying  in  a “kiln.”  The  barley  has  now  become 
“ malt.” 

2.  The  malt  is  ground  and  then  subjected  to  the  “mashing  ” 
process.  In  this  the  malt  is  treated  with  water  warmed  to  a 
proper  temperature.  The  change  of  starchy  matters  to  saccha- 


ALCOHOLS. 


71 


rine  matters  is  advanced  and  soluble  substances  are  dissolved.  A 
liquor  called  “wort  ” is  obtained. 

3.  The  wort  is  drawn  off,  hops  are  added,  and  the  liquid  is 
boiled ; later  it  is  drawn  off  again  and  carefully  cooled. 

4.  Next  yeast  is  added.  The  sugars  split  up  into  alcohol  and 
carbon  dioxide,  The  latter  as  it  rises  makes  the  liquid  foamy. 

5.  The  liquor  is  “racked  off”  so  as  to  separate  the  clear  part 
from  any  matter  that  would  make  the  beer  turbid. 


The  amount  of  alcohol  in  the  finished  beer  varies  from  three  to  eight  per  cent. 
In  some  cases,  beer  is  subjected  to  a process  called  pasteurization.  This  process 
consists  in  raising  the  beer  to  such  a temperature  that  the  microscopic  plants 
that  favor  fermentation  are  destroyed.  If  this  sort  of  sterilization  were  not  per- 
formed, the  vinous  fermentation  might  be  followed  by  an  acetous  fermentation  ; 
in  other  words,  the  beer  might  turn  sour. 


In  the  production  of  wines , grapes  are  commonly  used.  They 
are  often  selected  with  great  care.  Sometimes  they  are  separated 
from  the  stems  and  sometimes  not. 

1.  The  grapes  are  pressed,  care  being  taken  not  to  crush  the 
seeds  or  the  twigs.  The  juice  produced  is  called  “must,”  the 
solid  residue  is  called  “marc”  or  “pomace.”  The  must  contains 
grape  sugar  as  its  most  important  constituent.  Many  other  sub- 
stances have  been  recognized,  among  which  the  following  ought 
to  be  noted  : tartaric,  tannic,  malic,  and  other  acids,  albuminoids, 
coloring  matters,  mineral  matters,  notably  potassium  and  calcium 
compounds. 

2.  The  must  is  fermented.  This  process  will  commence  of 
itself  by  reason  of  microbes  in  the  air  or  on  the  grapes  used. 
Sometimes  carefully  selected  yeast  is  used  (the  kind  of  yeast  is 
of  the  highest  importance).  Fermentation  proceeds  slowly,  often 
for  months.  During  fermentation  the  sugar  changes  to  alcohol 
and  carbon  dioxide ; the  production  of  the  former  often  deter- 
mines the  separation  of  a sediment  called  “wine  lees”  or  “argol,” 
an  impure  potassio-calcium  tartrate  (a  crude  tartar,  of  consider- 
able importance  as  a source  of  cream  of  tartar  and  tartaric  acid.) 

3.  Other  operations  of  great  variety  are  carried  on.  They  are 
intended  to  alter  the  character  or  raise  the  quality  of  the  wine 
produced. 


72 


CARBON  COMPOUNDS. 


Sometimes  wine  is  pasteurized;  in  other  cases,  the  liquid  being  bottled  or 
•otherwise  enclosed,  the  fermentation  stops  by  reason  of  the  considerable 
accumulation  of  alcohol  which  suppresses  the  action  of  the  ferment  that  formed 
it.  Wines  contain  normally  from  seven  to  seventeen  per  cent,  of  alcohol.  In 
some  cases,  however,  the  amount  is  artificially  increased  by  adding  previously 
distilled  spirits. 

Spirits,  such  as'  whiskey,  brandy,  rum,  are  manufactured  by  first 
conducting  the  fermentation  process  and  afterward  the  distillation 
process.  The  fermentation  process  is  practically  similar  to  that 
detailed.  In  the  distillation  process,  the  fermented  liquor  is  dis- 
tilled and  a strong  alcohol  is  produced.  The  distilled  liquid  may 
contain  from  forty  to  fifty  per  cent,  of  alcohol,  the  remainder 
being  water — except  that  certain  etherial  compounds  are  present 
which  give  to  the  spirit  its  peculiar  flavor. 

Thus,  whiskey  contains  certain  compounds  derived  from  the  fermentation  of 
the  grain  from  which  it  is  produced.  Brandy,  being  distilled  from  wines,  con- 
tains flavoring  compounds  derived  from  the  grape,  while  rum,  which  is  distilled 
from  molasses,  has  a still  different  set  of  flavoring  compounds  referable  to  its 
origin. 


II.  Alcohols  with  Two  Atoms  of  Oxygen  (Glycols.) 

Many  members  of  this  group  are  known.  They  may  be  derived 
from  one  or  more  radicles  of  one  or  more  of  the  hydrocarbon 
series  already  mentioned. 

The  first  member  of  the  group  is  itself  called  glycol.  It  is 
ethylene  glycol,  C2H4(OH)2,  or  CH2OH*CH2OH. 


III.  Alcohols  with  Three  Atoms  of  Oxygen. 

Many  members  of  this  group  are  known.  The  most  important 
is  glycerine,  now  called  glycerol. 

Glycerin , now  called  glycerol,  (property l alcohol ),  C3H803,  or 
H2COH  * CHOH  * CH2OH.  This  is  a well-known  colorless  liquid 
of  syrupy  consistency.  It  has  a sweetish  taste.  It  mixes  readily 
with  alcohol  or  water.  Indeed,  when  exposed  to  ordinary  air,  it 
absorbs  moisture.  When  pure  it  may  be  distilled  without  decom- 
position. It  distils  better,  however,  in  contact  with  a current  of 
steam. 


ALCOHOLS. 


73 


Glycerol  is  produced  in  some  processes  of  fermentation  ; for 
example,  during  the  vinous  fermentation  of  sugar. 

Glycerol  is  ordinarily  manufactured  from  lard,  but  it  may  be 
produced  from  other  true  fats. 

Glycerin  was  recognized  by  Scheele  as  early  as  1779.  Chemical  knowledge 
on  this  subject  has  been  very  much  enlarged  since  by  the  studies  of  Chevreul, 
Berthelot,  and  others,  on  fats,  and  since  modern  manufacturing  operations 
have  produced  large  quantities  of  glycerin  in  response  to  modern  demands. 
There  are  two  general  methods  of  producing  this  substance : 

First,  by  the  process  of  saponification.  In  making  soap,  dry 
fats,  (that  is,  glycerides)  are  boiled  with  a strong  alkali.  This 
substance  combines  with  the  fat  acids,  forming  soap,  and  at  the 
same  time  liberates  glycerin.  The  soap  may  be  separated  from 
the  mixture,  and  so  may  the  glycerin. 

If,  instead  of  potassium  hydroxide  or  sodium  hydroxide,  lead 
oxide,  called  litharge,  PbO,  is  boiled  with  the  glyceride,  the  latter 
gives  rise  to  the  same  reaction,  only  the  salt  produced  is  called 
lead  soap.  It  may  be  classed  according  to  circumstances  as 
stearate,  palmitate,  or  oleate  of  lead,  or  a mixture  of  these  salts. 
The  lead  soap,  however,  different  from  soaps  of  the  alkalies,  is 
insoluble  in  water.  Thus,  it  is  more  easily  separated  from  the 
mixture,  and  it  gives  more  favorable  opportunity  for  subsequent 
separation  of  the  glycerin. 

Second,  natural  fats  may  be  dissociated  by  the  action  of  super- 
heated steam.  A separation  is  accomplished  whereby  the  glycerin 
sinks  to  the  bottom  of  the  mixture,  and  the  fatty  acids  rise.  The 
glycerin  may  be  drawn  off  subsequently,  and  subjected  to  further 
purification. 

Glycerin  has  a very  large  number  of  uses  in  pharmacy  and  in  other  arts. 
Generally  speaking,  it  is  a valuable  solvent.  It  does  not  solidify  readily,  and 
it  does  absorb  moisture.  On  this  account  it  is  employed  to  keep  membranes 
soft  and  pliable.  It  is  employed  for  certain  purposes  in  photography.  It  is 
said  to  be  used  very  much  in  brewing  operations  in  the  manufacture  of  beer. 
It  has  been  used  in  the  so-called  wet  gas  meters  in  place  of  water,  for  use 
during  the  prevalence  of  low  temperature.  Enormous  quantities  are  employed 
in  the  manufacture  of  nitroglycerin  for  use,  alone  or  with  other  substances, 
as  an  explosive. 

Nitroglycerin , property l trinitrate , C3H5(N03)3.  This  remarka- 
ble substance,  now  largely  used  as  an  explosive,  seems  to  have 


7 4 


CARBON  COMPOUNDS. 


been  brought  to  notice  as  a remedy  for  headache,  under  the  name 
of  glonoin  oil.  It  was  first  prepared  in  the  United  States  and 
recommended  as  a medical  remedy.  Its  explosive  properties 
were  soon  discovered  ; and  at  length,  as  other  nitrates,  such  as 
cellulose  nitrate  or  gun-cotton,  came  into  use,  nitro-glycerin  was 
carefully  studied.  The  great  development  of  this  explosive  may 
be  referred  largely  to  Alfred  Nobel,  who  introduced  it  for  use  in 
blasting.  Of  late,  it  has  come  to  be  very  extensively  employed 
on  great  public  works,  such  as  railway  tunnels,  where  large 
masses  of  rock  must  be  broken  down.  It  has  been  employed  to 
great  advantage  in  driving  deep  petroleum  wells.  If  a well 
which  has  attained  great  depth  fails  to  afford  oil,  a cartridge  is 
in  some  cases  lowered  to  the  bottom  and  then  exploded  by  elec- 
tricity ; thereupon  seams  appear  to  be  opened  in  the  subterranean 
rock,  through  which  oil  or  gas  may  flow.  This  method  has  been 
largely  used  in  Pennsylvania,  and  in  many  cases  has  successfully 
accomplished  its  purpose. 

It  is  a curious  fact  that  nitroglycerin  may  be  burned  without  any  explosion. 
It  is  exploded  best  by  some  form  of  percussion.  A cartridge  of  it  is  usually 
provided  with  a special  exploder  containing  fulminating  mercury.  The  ful- 
minate, being  decomposed  by  an  electric  spark,  strikes  a blow  upon  the  nitro- 
glycerin, which  itself  thereupon  explodes  with  frightful  force.  Many  terrible 
explosions  have  occurred  from  the  decomposition  of  nitroglycerin  by  some 
concussion  by  accident  or  otherwise.  On  account  of  such  danger,  it  has  now 
become  the  custom  where  great  public  works  demand  the  use  of  this  explosive, 
to  manufacture  it  upon  the  spot.  A small  house  is  usually  constructed  of  light 
materials,  and  it  is  surrounded  by  a parapet  of  earth.  Within  the  house  the 
explosive  is  manufactured.  In  case  of  an  accident,  the  loss  of  the  building  is 
not  material,  and  the  parapet  serves  to  localize  the  effects. 


Nitroglycerin  is  produced  by  the  action  .of  a mixture  of  concen- 
trated nitric  acid  and  concentrated  sulphuric  acid  upon  glycerin. 
The  mass  is  allowed  to  stand  for  some  time,  free  from  jarring  and 
in  a cool  place.  By  and  by,  nitroglycerin  separates  out  as  an  oily 
liquid.  It  is  drawn  off  into  water  and  thoroughly  washed.  This 
washing  is  of  the  first  importance,  since  acids  remaining  in  the 
nitroglycerin  are  liable  to  determine  a decomposition  of  the  latter 
with  violent  explosion. 

Nitroglycerin  is  rarely  used  alone.  It  is  ordinarily  mixed  with 
other  substances,  either  for  convenience  in  transportation  or 
otherwise  to  diminish  the  danger  of  handling.  The  commonest 


ALCOHOLS. 


7 5 


preparation  is  that  called  dynamite,  which  consists  of  three  parts 
of  nitroglycerin  absorbed  in  one  part  of  infusorial  earth.  This 
infusorial  earth  is  a mass  of  silicious  skeletons  of  microscopic 
vegetables.  It  is  very  porous  and  serves  to  hold  the  nitro- 
gylcerin  in  the  form  of  a paste.  This  paste  may  then  be  placed 
in  paper  wrappers  so  as  to  form  suitable  cartridges.  A cartridge 
of  dynamite  may  be  subjected  to  a more  severe  blow  than  an 
equivalent  mass  of  nitroglycerin,  for  the  dynamite  represents  a 
sort  of  paste  which  may  yield  to  the  blow  and  change  its  shape 
rather  than  to  suffer  contraction  as  the  nitroglycerin  alone 
seems  to. 

Many  frightful  accidents  have  occurred  from  the  careless  use  of  nitro- 
glycerine or  its  preparations.  If  the  subject  is  carefully  considered,  it  is  dis- 
covered that  many  of  these  accidents  are  largely  due  to  gross  carelessness. 
Thus,  in  some  cases,  a frozen  mass  of  nitroglycerin  has  been  placed  by  a work- 
man upon  a hot  stove  to  melt.  Again,  the  use  of  this  powerful  explosive  in 
quarrying  and  similar  blasting  operations  has  extended  enormously;  while  the 
accidents  appear  not  to  have  increased  in  like  proportion.  Thus  it  appears  that 
in  the  vast  majority  of  cases  it  is  used  with  entire  safety. 


Alcohols  with  Four,  Five,  Six,  Seven,  Eight,  Atoms  of 

Oxygen. 

To  the  six  set  belong  mannite  and  dulcite,  isomers,  white  solids 
sweet  in  taste,  derived  from  a vegetable  substance  called  manna  : 

Mannite,  C6H1406,  CH2OH(CHOH)4CH2OH 
Dulcite,  C6H1406,  CH2OH*C(OH)2*CH2(CHOH)2CH2OH 


CHAPTER  XI. 


ETHERS,  SIMPLE  AND  MIXED. 

Esters,  Etc. 

The  word  ether  was  originally  applied  to  what  is  now  known  as 
ethyl  ether ; it  now  applies  to  a class  of  organic  bodies  having  the 
general  formula  R — O — R,  in  which  R designates  an  alkyl  radicle 
like  ethyl,  C2H5.  If  the  two  alkyls  are  alike,  the  ether  is  called 
simple ; if  they  are  different,  the  ether  is  called  mixed. 

The  ethers  correspond  in  general  to  the  inorganic  metallic 
oxides,  for  example  : potassium  oxide,  K20,  or  K — O — K. 

There  are  two  important  general  methods  for  the  preparation 
of  ethers  : 

1.  By  action  of  alkyl  iodides  on  sodium  alcohols  : 

C2H5I  + NaOC2H5  = C2H5OC2H5  + Nal 

Ethyl  Sodium  Ethyl  Sodium 

iodide  ethide  ether  iodide 

2.  By  action  of  sulphuric  acid  on  an  alcohol.  (In  this  case  the  action  is 
virtually  a withdrawal  of  water.  The  operation  is,  in  fact,  more  complex.  It 
is  discussed  later.) 

2C2H5OH  = C2H5OC2H5  + h2o 

Ethyl  Ethyl  Water 

alcohol  ether 

(Mixed  ethers  may  be  produced  by  both  methods;  but  then  the  compounds 
used  must  have  different  alkyl  radicles.) 

The  first  fatty  ether,  methyl  ether  (CH3)20,  is  a gas,  at  ordi’ 
nary  temperature.  Advancing  in  the  series,  volatile  liquids  are 
found. 

It  is  a remarkable  fact  that  the  ethers  boil  at  lower  tempera- 
tures than  their  alcohols. 

Many  ethers  are  known,  also  many  substitution  products  and 
many  isomers. 


(76) 


ETHERS,  ESTERS,  ETC. 


77 


Dimethyl  ether , (CH3)20.  This  substance  is  worthy  of  mention 
because  it  corresponds  strictly  with  ethyl  ether,  the  latter  being 
the  anaesthetic  so  much  employed  in  surgery.  From  the  general 
laws  of  chemical  philosophy,  it  might  be  expected  that  methyl 
ether  would  be  more  volatile  than  ethyl  ether.  This  is  indeed 
the  case.  At  ordinary  temperatures  it  is  a colorless  gas,  but  at 
— 2 i°C  it  condenses  to  a colorless  but  very  volatile  liquid.  Just 
as  ethyl  ether  is  produced  by  the  action  of  sulphuric  acid  upon 
ethyl  alcohol,  so  methyl  ether  is  produced  by  the  action  of  sul- 
phuric acid  upon  methyl  alcohol. 

Ethyl  oxide , or  ethyl  ether  (commonly  called  sulphuric  ether), 
(C2H5)20.  This  substance  is  very  important,  both  from  the  theo- 
retical and  the  practical  side.  Its  power  of  producing  insensibility 
to  pain  has  led  to  its  wide-spread  employment  in  surgery.  Cer- 
tainly any  process  or  thing  that  diminishes  human  misery  must  be 
considered  as  useful  in  the  highest  degree. 

Sir  Humphry  Davy  and  others,  working  in  what  was  called  the  Pneumatic 
Institution  of  Dr.  Beddoes,  made  a number  of  experiments  upon  the  inhalation 
of  gaseous  vapors.  While  these  led  to  the  discovery  of  the  effects  of  nitrogen 
monoxide  (nitrous  oxide)  they  nearly  proved  fatal  to  Davy  himself.  Investiga- 
tion in  this  line  proceeded,  however,  and  in  1818  Faraday  observed  some  of  the 
physiological  properties  of  ether.  The  practical  application  of  this  substance 
seems  to  be  referable  to  Dr.  Long,  who  applied  it  in  1842.  Dr.  Morton,  of  Bos- 
ton, is  ordinarily  recognized  as  the  first  to  bring  its  use  to  public  attention  as 
an  adjunct  in  surgery.  His  claims  as  to  priority  have  been  disputed  by  Profes- 
sor Jackson,  of  Boston.  In  England,  Sir  James  Simpson,  of  Edinburgh,  appears 
to  have  been  the  pioneer  in  its  employment.  It  is  worthy  of  remark  with 
respect  to  ether,  that,  like  other  useful  and  valuable  inventions,  its  early 
progress  was  in  the  face  of  great  opposition. 


On  the  theoretical  side,  ether  has  been  very  carefully  studied 
because  of  certain  peculiarities  incidental  to  its  manufacture. 
The  substance  is  made  by  heating  together  under  proper  condi- 
tions, sulphuric  acid  and  alcohol.  It  was  soon  discovered  that  a 
given  amount  of  sulphuric  acid  was  capable  of  changing  into 
ether  a much  larger  quantity  of  alcohol  than  was  at  first  supposed 
possible.  This  possibility  was  published  by  a French  chemist, 
Cadet,  in  1774.  One  of  his  competitors,  Beaume,  objected  to 
Cadet’s  method.  The  latter  offered  the  capital  reply  that  he  was 
selling  his  product  at  forty  sous  an  ounce  while  Beaume  was 
charging  twelve  livres.  For  a long  time  the  nature  of  the  process 


78 


CARBON  COMPOUNDS . 


was  not  understood.  Eventually,  however,  its  careful  study 
resulted  in  important  contributions  to  chemical  theory. 

Ether  is  now  manufactured  by  what  is  called  the  continuous  process.  The 
apparatus  employed  consists  essentially  of  a retort,  a condenser,  and  a receiver. 
In  the  retort  the  transformation  of  alcohol  into  ether  proceeds.  - The  ether 
vapor  is  liquified  in  the  condenser  and  collected  in  the  receiver.  A mixture  of 
ethyl  alcohol  and  sulphuric  acid  is  introduced  into  the  retort.  Upon  heat- 
ing the  mixture  to  a proper  temperature,  ether  is  produced.  Now,  upon 
steadily  adding  more  alcohol,  in  properly  graduated  quantity,  the  same  portion 
of  sulphuric  acid  is  capable  of  carrying  on  the  transformation  of  the  alcohol 
continuously. 

The  present  theory  of  the  operation  is  as  follows  : The  change  from  alcohol 
to  ether  advances  through  an  intermediate  stage.  In  this  stage  there  is  pro- 
duced a compound  called  ethyl  sulphuric  acid,  C2H13HSO4.  With  this  fact  in 
mind,  the  following  explanation  may  be  understood.  When  sulphuric  acid  is 
heated  with  ethyl  alcohol,  ethyl  sulphuric  acid  is  first  produced  in  accordance 
with  the  following  equation  : 


C2H5) 

H) 

C2H5-) 

H) 

[0 

+ 

fso4 

= > S04 

+ 

f° 

hJ 

hJ 

hJ 

Hj 

Next,  the  ethyl  sulphuric  acid  acts  upon  a new  portion  of  ethyl  alcohol, 
whereby  two  most  important  results  are  attained.  First,  ethyl  ether,  the  thing 
desired,  is  produced.  Second,  sulphuric  acid,  the  reagent  desired  for  subse- 
quent operations,  is  formed  anew.  This  second  stage  may  be  understood  by  a 
consideration  of  the  following  equation  : 


H1 

1 C2H5] 

1 C2h5  : 

) H) 

1 

,0  + 

>-  S04  = 

> O + [ SO4 

c2h5J 

1 H 

1 c2h5  ! 

> hJ 

While  then,  theoretically,  the  process  is  continuous  because  of  the  continu- 
ous reproduction  of  sulphuric  acid,  it  is  found  practically  that  certain  conditions 
interfere  with  the  perfect  working  of  the  operation  which  make  it  necessary  to 
employ  from  time  to  time  a small  additional  supply  of  material. 

Ether  has  other  uses  beside  those  in  surgery.  It  is  a valuable 
solvent  for  fats.  It  is  used  in  the  preparation  of  collodion,  which 
is  a solution  of  nitrocellulose  in  ether.  It  has  been  largely 
employed  in  the  artificial  production  of  ice,  although  at  present 
ammonia  gas  is  replacing  it  in  this  process. 

Esters,  or  Etherial  Salts. 

An  ester  is  a salt  containing  an  alkyl  radicle,  or  its  equivalent. 
Thus  ethyl  acetate,  C2H5-OOC'CH3  is  an  ester  ; hydrogen  ethyl 
sulphate,  HC2H5S04  is  an  ester  ; ethyl  chloride,  C2H5C1  is  an 
ester. 


ETHERS , ESTERS,  ETC. 


79 


A diatomic  alcohol  may  form  more  than  one  ester.  Thus 
glycol,  C2H4(OH)2  may  form 


The  basic  ester,  0HC2H4*C1 
The  neutral  ester,  C1*C2H4*C1 


Esters  occur  in  nature  in  fruits  and  flowers  ; these  often  owe 
their  odors  to  one  or  more  esters  present. 

There  are  many  general  methods  of  forming  esters  : 

1.  By  direct  action  of  an  acid  upon  an  alcohol. 

2.  By  exchange  between  an  alkyl  iodide  and  a silver  salt  of  the  acid  whose 
ester  is  to  be  formed. 

The  esters  are  generally  volatile  liquids,  possessing  agreeable 
odors,  lighter  than  water,  insoluble  or  but  slightly  soluble  in 
water,  soluble  in  alcohol. 

The  esters  are  generally  easy  of  decomposition.  Calcium 
oxide  and  barium  oxide  (dry)  generally  act  on  esters  so  as  to 
form  two  kinds  of  compounds  : in  the  one  the  metal  combines 
with  the  acid  radicle  of  the  ester;  in  the  other  the  metal  com- 
bines with  oxygen  and  the  alkyl  radicle. 

The  following  esters  are  worthy  of  mention  : 

Methyl  chloride,  CH3CI,  see  p.  62. 

Chloroform,  CHCI3,  see  p.  63. 

Ethyl  chloride,  C2H5CI,  see  p.  17. 

Ethyl  nitrite  (sweet  spirit  of  nitre),  C2H5NO2 
Ethyl  nitrate  (nitric  ether),  C2H5NC>3 
Ethyl  sulphate,  (C2H5)2S04 
Hydrogen  ethyl  sulphate,  HC2H5S04 

Propenyl  trinitrate  (nitroglycerin),  C3H5(N03)3,  see  p.  73. 

Methyl  butyrate,  (pineapple  oil),  CH3*OOC*C3H7 
Ethyl  acetate  (acetic  ether),  C2H5*OOC*CH3 
Amyl  acetate  (pear  oil),  CsHn'OOC.CHs 


Sulphur  (and  other)  Alkyl  Compounds. 


The  alkyl  radicles  are  capable  of  forming  a series  of  compounds  correspond- 
ing to  many  of  the  oxygen  organic  compounds  already  mentioned,  except  that 
oxygen  is  replaced  by  sulphur  or  selenium  or  tellurium.  The  sulphur  alcohols 
are  called  mercaptans . For  example  : 


Ethyl  alcohol,  C2H-OH 
Ethyl  ether,  (C2H0)_O 


Ethanethiol,  C2H5SH 
Ethanethioethane,  (C2H5)2S 


CHAPTER  XII. 


ORGANIC  ACIDS. 

Fatty  Series. 

The  organic  acids,  like  the  compounds  already  referred  to,  are 
usually  divided  into  two  series,  the  fatty  and  the  aromatic.  Only 
the  fatty  will  be  discussed  here. 

It  is  not  easy  to  make  a comprehensive  definition  of  the  term 
organic  acid. 

The  stronger  organic  acids  have  certain  common  properties  in 
marked  degree:  (i)  They  have  sour  taste;  (2)  they  redden  blue 
litmus  ; (3)  they  combine  with  metals  to  form  salts  ; (4)  they  neu- 
tralize alkalies,  forming  salts  ; (5)  they  act  on  metallic  carbonates 
liberating  carbon  dioxide  and  forming  salts ; (6)  when  they  form 
salts  as  described,  a part  of  the  hydrogen  of  the  acid  is  replaced 
by  metal.  But  some  organic  substances  recognized  as  acids  do 
not  perform  all  of  the  acts  described. 

The  organic  acids  contain  one  or  more  groups  of  the  radicle 
hydroxyl,  COOH. 

Some  of  the  organic  acids  exist  free  in  animal  or  vegetable  matters;  some 
exist  there  in  a state  of  combination  ; some  are  produced  by  processes  of  natural 
fermentation  or  decay;  some  are  produced  by  distinctly  artificial  chemical 
operations. 

The  organic  acids  may  be  obtained  by  a great  variety  of  methods,  generally 
by  mere  processes  of  separation  including  liberation  by  other  stronger  acids  ; 
in  many  cases  even  the  acids  known  in  nature  may  be  built  up  synthetically 
from  lifeless  elementary  substances. 

Each  organic  acid  is  considered  to  be  derived  by  oxidation  from  a correspond- 
ing parent  alcohol. 

Some  of  these  acids  are  gaseous,  some  are  liquid,  some  are  solid,  at  ordinary 
temperatures.  Generally  they  are  soluble  in  water;  but  some  are  not. 

The  number  of  fatty  acids  known  is  very  great ; many  isomers 
and  substituted  compounds,  also  acids,  are  recognized. 

(80) 


FATTY  ACIDS. 


Si 


Classification  of  the  fatty  acids  is  somewhat  difficult.  It  is 
usually  dependent  upon  the  number  of  oxygen  atoms  in  the  mole- 
cule. Thus,  starting  with  that  acid  having  two  atoms  of  oxygen, 
the  series  advances,  step  by  step,  to  that  having  fourteen  atoms ; 
one  having  twenty-eight  atoms  of  oxygen  is  known.  Thus  about 
sixteen  groups  are  recognized ; in  many  cases,  however,  these  are 
divided  into  several  subordinate  classes. 


Conspectus  of  Fatty  Acids. 


Acids  of  the  series  A,  B,  C,  D,  etc.,  contain  respectively  radicles  of  the  for- 
mulas Cn  H211  , Cn  H2n  — ■ 2>  Cn  H211  — 4 > Cn  H2Q  — 65  CtC. 

1st.  Acids  with  two  atoms  of  oxygen.  (Representatives  are  known  of  all  the 
four  series  of  fatty  hydrocarbons,  A,  B,  C,  D.)  Examples : A.  Many  acids 
of  the  series  commencing  with  formic  acid. — B.  Many  acids  of  the  acrylic 
series  : oleic  acid. — C and  D. 

2d.  Acids  with  three  atoms  of  oxygen.  (Representatives  are  known  of  all 
the  four  series,  A,  B,  C,  D.)  Examples  : A.  Carbonic,  glycollic,  lactic  acids. 
— B.  Ricinoleic  acid. — C and  D. 

3d.  Acids  with  four  atoms  of  oxygen.  (Representatives  of  six  series,  A,  B, 
C,  D,  E,  F.)  Examples:  A — B.  Oxalic,  malonic,  succinic,  suberic  acids. — 
C.  Fumaric  and  maleic  acids. — D,  E,  F. 

4th.  Acids  with  five  atoms  of  oxygen.  (Representatives  of  five  series,  A,  B, 
C,  D,  E.)  Examples  : A — B.  Malic  acid. — C,  D,  E. 

5th.  Acids  with  six  atoms  of  oxygen.  (Representatives  of  five  series,  A,  B, 
C,  D,  E.)  Examples : A — B.  Tartaric  acid. — C,  D,  E. 

6th.  Acids  with  seven  atoms  of  oxygen.  (Representatives  of  six  series,  A, 
B,  C,  D,  E,  F.)  Examples : A — B — C.  Citric  acid. — D,  E,  F. 

7th.  Acids  are  known  with  eight,  nine,  ten,  eleven,  twelve,  thirteen,  four- 
teen, sixteen,  twenty,  and  twenty-eight  atoms  of  oxygen.  In  some  of  these 
there  are  several  series. 

The  total  number  of  fatty  acids  known  is  very  great.  Only  a few  can  be 
mentioned. 


6 


82 


CARBON  COMPOUNDS. 


I,  Fatty  Acids  Containing  Two  Atoms  of  Oxygen,  CnH2n02. 


c h2  o2 

Formic  acid 

c2  h4  o2 

Acetic  “ 

c3  h6  o2 

Propionic  “ 

c4  h8  o2 

Butyric  “ 

C5  H10  02 

Valeric  “ 

C6  H42  02 

Caproic  (or  hexoic)  acid 

c7  h14  o2 

Oenanthylic  (or  heptoic)  acid 

c8  h16  o2 

Caprylic  “ 

C9  His  02 

Pelargonic  “ 

C10  H20  02 

Capric  . “ 

C11  h22  o2 

Undekylic  “ 

c42  h24  o2 

Laurie  “ 

C13  h26  o2 

Tridekylic  “ 

c14  h28  o2 

Myristic  “ 

C15  H30  O2 

Isocetic  “ 

Ci6  H32  o2 

Palmitic  “ 

C17  h34  o2 

Margaric  “ 

Ci8  h36  o2 

Stearic  “ 

C19  H38  O2 

Nondekylic  “ 

C2o  H4q  02 

Arachidic  “ 

C22  H44  O2 

Behenic  “ 

c24  h48  o2 

(not  named) 

C25  H50  02 

Hyaenic  “ 

C27  Hj4  O2 

Cerotic  “ 

C30  Heo  02 

Melissic  “ 

C34  h68  o2 

Dicetylacetic  “ 

Formic  acid , HOOCH.  This  acid  occurs  in  the  bodies  of  cer- 
tain red  ants ; also  in  certain  stinging  nettles.  It  was  noticed  as 
early  as  1670,  when  from  red  ants  an  acid  substance  was  produced 
which  was  then  recognized  as  in  some  sense  corresponding  to 
acetic  acid. 

Formic  acid  may  be  looked  upon  as  methyl  alcohol  in  which  one  atom  of 
oxygen  has  replaced  two  atoms  of  hydrogen.  Thus  : 

Methyl  alcohol  CH3OH 

Formic  acid  CHOOH 

Formic  acid  is  ordinarily  prepared  by  a destructive  distillation 
of  oxalic  acid.  The  oxalic  acid  mixed  with  glycerine  is  heated  in 


FATTY  ACIDS. 


83 


a flask  provided  with  an  evolution  tube,  the  tube  being  dipped 
into  a suitable  receiver ; by  the  hot  bath  of  glycerine  the  oxalic 
acid  is  decomposed,  with  the  production  of  formic  acid  and  other 
substances.  The  formic  acid  may  be  collected  in  the  receiver  as 
a colorless  liquid.  Formic  acid  is  a liquid  that  has  a peculiar  and 
painful  effect  upon  the  skin.  It  acts  upon  metallic  oxides  form- 
ing a large  number  of  perfectly  definite  formates.  Cupric  for- 
mate, a blue  salt,  soluble  in  water,  is  an  example. 

Acetic  acid,  HOOC*CH3.  The  ancients  were  well  acquainted 
with  acetic  acid  in  its  crude  form  in  vinegar.  They  knew  that 
when  the  fermentation  of  wine  proceeds  to  a certain  degree,  a 
sour  substance  is  produced.  Moreover,  they  used  the  substance 
as  a sort  of  chemical  solvent  in  addition  to  its  employment  as  a 
condiment. 

“ The  ancients  held  exaggerated  views  respecting  the  solvent 
power  possessed  by  vinegar.  This  is  shown  by  the  well  known 
story  related  by  both  Livy  and  Plutarch,  of  Hannibal  dissolving 
the  Alps  by  means  of  vinegar ; whilst  Vitruvius  states  that  sili- 
cious  rocks  which  can  be  attacked  neither  by  the  chisel  nor  by 
fire,  are  dissolved  when  heated  and  then  moistened  with  vinegar.” 

There  are  four  general  methods  employed  in  the  preparation  of 
acetic  acid  : (1)  by  the  acetous  fermentation  of  ethyl  alcohol  ; 

(2)  by  chemical  oxidation  of  ethyl  alcohol ; (3)  by  the  dry  distil- 
lation of  carbohydrates,  such  as  wood  and  other  organic  sub- 
stances ; (4)  by  liberation  from  its  salts,  the  acetates. 

(1)  When  sugar  undergoes  the  vinous  fermentation  into  ethyl  alcohol  in 
the  preparation  of  wine,  beer,  and  similar  liquids,  there  is  always  a tendency 
toward  a further  fermentation  called  the  acetous , whereby  the  ethyl  alcohol 
changes  into  acetic  acid.  The  acetous  fermentation  proceeds  under  the  influ- 
ence of  the  growth  of  a peculiar  microbe  called  inycoderma  aceti ; but  the  proc- 
ess is  essentially  an  oxidizing  one,  and  access  of  air  is  necessary.  In  the 
commercial  production  of  acetic  acid,  large  casks  are  provided.  They  are 
partly  filled  with  shavings  of  wood.  Upon  the  wood  a certain  portion  of 
vinegar  is  poured.  This  vinegar  contains,  already,  microbes  capable  of  carry- 
ing on  acetous  fermentation.  In  due  time,  alcohol  or  some  alcoholic  liquid  is 
added.  Fermentation  soon  sets  up  whereby  the  alcohol  is  turned  into  acetic 
acid,  air  being  furnished  through  perforations  provided  at  certain  suitable 
points  in  the  cask. 

The  process,  which  was  formerly  an  empirical  one,  has  been  carefully  studied, 
so  that  now  it  is  placed  upon  a thoroughly  scientific  basis.  It  is  recognized 
that  the  temperature  should  be  maintained  neither  too  high  nor  too  low ; if  too 


84 


CARBON  COMPOUNDS. 


high,  alcohol  is  lost  by  evaporation  ; if  too  low,  fermentation  does  not  proceed 
with  sufficient  rapidity.  It  is  well  known  that  a graduated  supply  of  air  is 
requisite,  and  this  is  carefully  provided.  Further,  the  proper  kind  of  microbes 
must  be  present. 

{2)  In  the  chemical  oxidation  of  alcohol,  this  substance  changes  first  into 
aldehyde,  C2H4O ; and  then  into  acetic  acid,  CH3COOH.  This  process  maybe 
■employed  to  demonstrate  the  chemical  formation  of  acetic  acid,  but  it  has  not 
.yet  been  successful  as  an  industrial  operation.  In  order  to  conduct  it  a series 
•of  shelves  supporting  shallow  dishes  of  alcohol  and  small  masses  of  platinum 
hlack,  are  provided,  and  the  whole  is  encased  in  a glass  chamber.  The  vapors 
of  alcohol,  coming  in  contact  with  the  platinum  black,  undergo  a slow  oxida- 
tion. The  acetic  acid,  thereby  formed,  trickles  down  the  glass  walls  of  the 
receiver  into  a tray  at  the  bottom  of  the  contrivance. 

(3)  Large  quantities  of  acetic  acid  are  now  produced  by  the  dry  distillation 
of  wood.  The  apparatus  employed  consists  of  a suitable  retort,  with  a furnace 
which  heats  it,  and  appropriate  condensers  and  receivers.  The  wood  being  intro- 
duced into  the  retort  and  the  temperature  being  raised  by  the  fire,  the  cellulose 
of  the  wood  undergoes  decomposition.  Many  substances  are  produced.  Among 
these  are  water,  methyl  alcohol  (see  page  66) , tarry  matters,  and  acetic  acid. 
The  acetic  acid  in  its  crude  form,  as  thus  manufactured,  is  known  as  pyro- 
ligneous acid.  In  this  form  it  is  used  in  some  of  the  processes  of  calico  print- 
ing. 

For  certain  purposes,  this  crude  acid  is  purified.  Thus  it  is  treated  with  lime 
in  quantity  sufficient  to  combine  with  the  acetic  acid.  By  this  means  a salt 
called  acetate  of  lime  is  produced,  but  the  tarry  matters  are  still  mingled  with 
it.  The  mixture  of  acetate  of  lime  and  its  impurities,  is  subjected  to  a heating 
or  roasting  process  sufficient  to  char  the  impurities  and  yet  leave  the  acetate 
uninjured.  Subsequently  the  acetate  is  decomposed  by  the  use  of  sulphuric 
acid  or  hydrochloric  acid.  When  sulphuric  acid  is  employed,  the  reaction  pro- 
duces not  only  free  acetic  acid,  it  also  produces  sulphate  of  lime.  The  latter  is 
a thick  pasty  substance.  The  pasty  mass  may  be  subjected  to  pressure  in  bags, 
whereby  the  liquid  containing  the  acetic  acid  is  squeezed  out  of  the  mass. 
When  hydrochloric  acid  is  used,  a very  soluble  calcium  chloride  is  produced. 
The  liquid  mixture  from  this  operation  is  usually  introduced  into  the  retorts 
and  distilled.  Acetic  acid  going  off  in  the  form  of  vapor,  is  afterward  con- 
densed in  suitable  coolers  and  brought  to  the  liquid  form. 

(4)  When  the  metallic  salts  called  acetates  are  acted  upon  by  suitable  acids, 
acetic  acid  is  liberated.  The  principle  of  this  operation  is  very  simple.  It  is 
the  same  as  that  just  presented  in  the  description  of  the  purification  of  pyro- 
ligneous acid.  Practically  any  salt  of  acetic  acid  may  be  employed. 


Acetic  acid  when  pure  is  a colorless  liquid  of  a distinctly 
acid  taste  and  smell.  Upon  the  addition  of  suitable  amounts  of 
heat,  it  may  be  changed  into  vapor  ; while,  under  the  influence 
of  cold,  it  condenses  to  a solid. 

Acetic  acid  combines  with  most  of  the  metals  to  form  the  salts 
known  as  acetates. 


FATTY  ACIDS. 


*5 


Steps  by  which  the  rational  formula  of  acetic  acid  is  secured. 
The  following  statement  is  introduced  as  an  illustration  of  meth- 
ods employed  in  organic  chemistry  for  discovering  the  molecular 
constitution  of  bodies  : 

1st.  Direct  organic  analysis  has  shown  that  the  empirical  formula  of  acetic 
acid  is  C2H402- 

2d.  With  potassium,  and  other  monad  metals,  acetic  acid  forms  but  one 
acetate;  in  this  one-fourth  of  the  hydrogen  of  the  acid  is  expelled  by  the  metal. 

Then  one  atom  of  hydrogen  is  different  in  function  from  the  other  three 
atoms. 

Then  acetic  acid  may  be  written,  H*C2H302. 

3d.  By  electrolysis  of  potassium  acetate,  two  different  carbon  compounds  are 
liberated  : ethane,  C2H6,  and  carbon  dioxide,  CO2.  The  reaction  is  believed  to 
be  in  effect : KC2H3O2  = K -f-  CO2  CH3.  (The  liberated  potassium  acts  on 
the  water  and  carbon  dioxide;  the  methyl  polymerises  into  ethane,  2CH3  = 
C2H6. 

Then  one  atom  of  carbon  in  acetic  acid  is  closely  connected  to  oxygen  and 
one  to  hydrogen. 

Again,  acetates  readily  yield  acetone  (whose  formula  has  been  made  out 
otherwise  to  be  CH3-COCH3).  And  acetone  readily  yields  acetic  acid  again, 
changes  which  evidently  do  not  profoundly  disturb  molecular  arrangement. 
Now  acetone,  when  treated  with  chlorine  forms  dichlor  acetone,  CH3-CCl2*CH3, 
a compound  whose  structure  is  not  substantially  different  from  that  of  acetone. 

These  facts  confirm  the  opinion  that  acetic  acid  holds  the  group  carbonyl, 
CO. 

Then  acetic  acid  may  be  written,  H*COCH30. 

4th.  When  phosphorus  trichloride  acts  on  organic  bodies  it  often  with- 
draws hydroxyl,  HO.  When  acting  on  acetic  acid  it  withdraws  one-fourth 
of  the  hydrogen  present  and  one-half  of  the  oxygen  present: 

H-C0-CH30  + PC13  = CH3-CO*Cl  + POC1  + HC1 

Here  then,  hydroxyl,  HO,  has  been  withdrawn. 

This  shows  that  probably  acetic  acid  contains  the  group  HO. 

Then  acetic  acid  may  be  written  HO*OC*CH3. 

5th.  By  graduated  action  of  chlorine  on  acetic  acid,  three-fourths  of  the 
hydrogen  present  are  replaced  step  by  step  — but  the  last  fourth  is  not  so 
replaced.  The  three  compounds  produced  are  acids  but  slightly  differing  from 
acetic  acid  ; they  are 

Monochloracetic  acid,  HOOC-CH2C1 
Dichloracetic  “ HOOC-CHC12 
Trichloracetic  “ HOOC*CC13 

These  show,  first , that  the  acetic  acid  has  not  been  disturbed  structurally, 
and  second,  that  three  atoms  of  hydrogen,  while  different  in  function  from  the 
fourth  atom,  are  practically  equivalent,  one  to  another. 

Then  three  atoms  of  hydrogen  do  not  need  to  be  separated  in  the  formula. 

Then  acetic  acid  may  have  its  formula  stand  as  HOOC*CH3. 

(In  addition,  there  are  a great  many  other  chemical  grounds  for  the  decision 
reached.) 


86 


CARBON  COMPOUNDS. 


Acetate  of  lead,  sometimes  called  sugar  of  lead,  is  largely  used 
in  the  arts.  It  is  ordinarily  prepared  by  dissolving  lead  oxide, 
called  litharge,  in  acetic  acid.  The  acetate  of  lead  formed  sep- 
arates out  in  well  defined  crystals.  Two  kinds  of  acetate  of  lead 
appear  in  commerce  : the  one,  somewhat  impure,  called  brown 
sugar  of  lead  ; and  the  other,  a higher  grade,  called  white  sugar 
of  lead.  Acetate  of  lead  is  largely  employed  in  the  manufacture 
of  the  acetates  of  aluminium  and  of  iron  for  use  in  calico  print- 
ing. 

Aluminium  acetate  is  produced  by  double  decomposition 
between  either  aluminium  sulphate  or  alum  and  acetate  of  lead. 
The  lead  and  the  sulphuric  acid  radicle  combine  to  form  plumbic 
sulphate,  a white  precipitate,  which  deposits  at  the  bottom  of  the 
vessel.  The  other  constituents  form  aluminium  acetate  which 
remains  in  the  liquid.  This  liquid  goes  by  the  name  of  red  liquor 
in  calico  printing  because  it  is  largely  used  as  a mordant  in  pro- 
ducing red  and  pink  colors. 


The  term  mordant  is  ordinarily  employed  as  a name  for  a mineral  substance 
which  has  the  power  of  chemically  uniting  with  vegetable  or  animal  dye  stuffs 
to  produce  a new  compound,  the  latter  often  possessing  a color  far  different 
from  that  of  its  components.  When  cloth  is  treated  first  with  a mineral  mor- 
dant and  then  with  a vegetable  or  animal  dye  stuff,  the  new  colored  compound 
is  formed  in,  upon,  or  between  the  fibres  of  the  textile  material.  The  color  is 
usually  firmly  fixed  there,  and  does  not  wash  out  as  a mere  stain  of  coloring 
matter  woul^.  The  principal  kinds  of  dyeing  involve,  therefore,  the  use  of 
mordants. 


Now,  aluminium  compounds  are  generally  excellent  mordants. 
The  aluminium  acetate,  or  red  liquor  is  oftener  employed  partly 
on  account  of  the  property  of  aluminium  compounds  just  men- 
tioned and  partly  because  the  acetic  acid  is  very  favorable  on 
account  of  its  volatility.  In  calico  printing,  red  liquor  mixed  with 
starch  is  printed  from  an  engraved  roller  upon  cotton  cloth.  The 
whole  is  thoroughly  dried  and  then  is  subjected  to  a further 
heating  sufficient  to  expel  most  of  the  volatile  acetic  acid.  The 
aluminic  oxide  or  other  compound  still  remaining  in  the  cloth  is 
in  a suitable  condition  to  act  as  a mordant ; for,  if  the  goods  are 


FATTY  ACIDS . 


87 


now  dipped  in  a solution  containing  alizarin  or  other  suitable 
animal  or  vegetable  dyestuff,  chemical  action  quickly  proceeds 
and  the  cloth  is  dyed. 

Ferrous  acetate  is  often  used  in  calico  printing  in  the  form  of  a 
liquid  called  black  liquor  or  iron  liquor.  Iron  compounds  are 
very  favorable  for  use  as  mordants,  vast  quantities  being  used,  in 
various  forms  of  the  dyer’s  art,  chiefly  for  producing  blacks  or 
other  dark  shades.  Iron  liquor  is  usually  manufactured  by  steep- 
ing iron  filings  in  crude  pyroligneous  acid.  The  acetic  acid 
quickly  attacks  the  iron,  forming  an  acetate.  Considerable  heat 
is  evolved,  and  this  favors  further  solution  of  the  metal. 


In  calico  printing,  acetate  of  iron  mixed  with  starch  into  a paste,  is  often 
printed  at  the  same  time  as  red  liquor.  Even  other  pastes  may  be  printed 
simultaneously  with  these.  As  many  as  twenty  different  pastes  may  be  applied 
to  calico  at  the  same  time  by  the  use  of  different  rollers.  These  different  pastes, 
each  being  applied  in  proper  spots  or  on  proper  places,  side  by  side  or  alternat- 
ing, or  in  some  cases  overlapping,  are  subsequently  dried  thoroughly,  as 
already  described  in  case  of  red  liquor.  When  the  cloth  is  brought  into  the 
dye  tub,  the  different  mordants  combine,  according  to  their  affinities,  with  one 
or  several  dye  stuffs  present,  and  thus  produce  a variety  of  different  colors  and 
designs  upon  the  cloth.  Madder  root  has  long  been  employed  for  the  prepara- 
tion of  calicoes  in  accordance  with  the  principles  here  stated.  Indeed,  the  gen- 
eral method  has  long  been  known  as  madder  dyeing,  and  the  goods  are  often 
spoken  of  as  madder  styles.  Of  late  years,  a wonderful  improvement  has  been 
introduced  whereby  the  starch  paste,  the  mordant  and  the  dye  stuff  are 
printed  on  the  cloth  at  one  operation  — chemical  combination,  however,  being 
prevented  by  suitable  methods.  The  cloth,  after  drying,  does  not  show  its 
proper  final  coloring.  The  complete  result  is  brought  about  by  suspending  the 
cloth  of  this  stage  in  a large  iron  chamber  and  then  subjecting  it  to  high  pres- 
sure steam  — the  heat  and  moisture  furnishing  the  conditions  necessary  for 
chemical  union  of  mordant  and  dye  stuff.  The  true  dyeing  operation  goes  on 
under  these  conditions  of  steaming,  and  thus  the  proper  colors  are  developed 
without  the  cloth  ever  being  dipped  into  the  old-fashioned  dye  tub. 

Propionic  acid , HOOC'CsHs.  This  acid  exists  in  certain  fruits, 
in  perspiration,  in  crude  wood  vinegar. 

It  may  be  prepared  by  the  action  of  sulphuric  acid  and  potas- 
sium dichromate  on  propyl  alcohol,  C3H7OH. 

It  is  liquid  at  ordinary  temperatures.  It  has  a sharp  odor. 

Butyric  acid , HOOC'C3H7  (2  forms  possible).  Butter  con- 
tains a glyceride  of  butyric  acid  ; when  the  butter  turns  rancid,  a 
portion  of  the  acid  is  set  free. 


88 


CARBON  COMPOUNDS. 


It  is  usually  prepared  by  fermentation  of  calcium  lactate ; cal- 
cium butyrate  is  formed  and  later  from  this  butyric  acid  is  sepa- 
rated. 

’ It  is  a liquid  having  a sharp,  rancid  odor. 

It  readily  forms  salts  with  the  metals  and  with  the  alkyl  radi- 
cles. Of  these,  ethyl  butyrate  has  a very  aromatic  and  fruit-like 
odor.  On  this  account  the  substance  is  prepared  in  the  arts  for 
use  as  a flavoring  extract  for  certain  kinds  of  confectionery. 

Valeric  acid , HOOC’C4H9  (4  forms  possible).  It  occurs  in 
crude  wood  vinegar.  It  may  be  obtained  from  valerian  root  by 
distillation. 

It  is  a liquid  having  a sharp  odor  resembling  that  of  butyric 
acid. 

Caproic  acid \ HOOC’CsHn  (8  forms  possible).  Certain  forms 
of  this  acid  exist  in  butter  whether  made  from  cows’  milk  or 
from  goats’  milk.  It  also  exists  in  certain  other  fatty  substances, 
for  example,  in  cocoanut  oil. 

Oenanthylic  acid,  HOOC‘C6H13  (17  forms  possible).  Acids  of 
this  set  are  produced  by  certain  kinds  of  fermentation. 

The  acids  are  either  liquids  or  easily  melted  solids. 

Caprylic  acid , HOOC’C7H15.  The  normal  acid  exists  as  a gly- 
ceride in  butter,  in  cocoanut  oil.  It  exists  free  in  fusel  oil  (a 
product  of  the  fermentation  of  grain),  in  certain  kinds  of  rank 
cheese. 

The  acid  forms  crystals  at  ordinary  temperatures. 

Pelargonic  acid , HOOC*C8H17,  exists  in  pelargonium  roseum . 
Capric  acid , HOOC*C9H19,  exists  in  butter,  cheese,  cocoanut  oil, 
etc.  Undekylic  acid , HOOC'C10H21,  may  be  prepared  from  certain 
other  organic  compounds.  Laurie  acid , HOOC-CnH23,  exists  in 
combination  in  bayberry  wax.  Tridekylic  acid \ HOOC‘C12H25, 
may  be  prepared  from  other  organic  compounds.  Myristic  acid , 
HOOCC13H27,  exists  in  certain  vegetable  oils.  Isocetic  acid , 
HOOC‘C14H29,  exists  in  the  oil  of  certain  seeds. 


FATTY  ACIDS. 


89 


Palmitic  acid , 
Margaric  acid, 
Stearic  acid, 


HOOOC15H31 

HOOOC16H33 

HOOC-Ci7H35 


These  acids  exist,  in  the  state  of 
combination  known  as  glycer- 
ides, in  a vast  number  of  ani- 
mals and  plants. 


The  fatty  or  oily  matters,  having  been  separated  by  heating  and 
straining  or  otherwise,  are  decomposed  into  the  fat  acids  and 
glycerin. 

The  three  acids  mentioned  are  solids  at  moderately  low  natural 
temperatures.  But  they  easily  melt  with  slight  heating.  As 
their  melting  points  are  different,  a mixture  of  the  acids  can  be 
separated  by  partial  cooling  followed  by  pressing  ; that  is,  if  the 
mixture  of  the  acids  is  held  for  some  hours  at  a temperature  at 
which  one  is  solid  while  the  others  are  liquid ; then  by  pressing, 
in  a filter  press  or  otherwise,  the  solid  acid  is  retained  as  a cake, 
while  the  liquid  ones  pass  through.  Then  the  process  may  be 
repeated  and  a more  complete  separation  secured. 

Stearic  acid  is  used  in  the  manufacture  of  candles. 

The  three  acids  mentioned  (and  some  others  beside)  are  capa- 
ble of  forming  true  salts  (soaps)  with  metals  or  their  oxides  or 
hydroxides.  Some  of  these  soaps  are  soluble  in  water,  alcohol, 
etc.,  and  some  are  insoluble.  They  will  be  discussed  in  brief 
under  the  title,  soap. 

Oils  and. Fats. 


Before  discussing  the  true  oils  and  fats,  glycerides,  some  com- 
ment on  the  word  oil  is  demanded. 


Oil  of  vitriol,  petroleum  oil,  oil  of  lemons,  lard  oil,  are  substances  in  whose 
names  the  word  oil  was  incorporated  from  a superficial  resemblance  of  the 
compounds.  Chemical  study  has  shown,  however,  that  the  substances  men- 
tioned are  very  different.  Oil  of  vitriol  is  not  an  organic  compound  at  all, 
and  resembles  the  other  substances  mentioned  merely  in  the  way  in  which  it 
flows  when  poured.  Several  of  the  other  oils  mentioned  resemble  one  another 
in  facts  like  that  of  producing  a translucent  spot  on  paper.  Petroleum  oils  con- 
sist chiefly  of  different  hydrocarbons  of  the  paraffin  series  mingled  together. 
The  oil  of  lemons  belongs  to  a class  of  substances  called  volatile  or  essential  oils. 
It  has  the  composition  CioH16.  It  is  a hydrocarbon  of  the  io-carbon  series,  and 
should  in  no  very  distinct  chemical  sense  be  classified  with  the  other  oils  men- 
tioned. Lard  oil  belongs  to  the  group  of  fatty  oils  known  as  glycerides.  They 
are  organic  salts  and  may  be  classed  as  esters.  They  are  compounds  of  glycyl 
and  certain  characteristic  fatty  acids.  Most  natural  fats  contain  more  than  one 
glyceride.  As  early  as  1820,  Chevreul  made  a careful  examination  of  natural 
fats.  As  a result,  he  declared  that  they  consist  of  mixtures  of  organic  salts,  the 
salts  being  generally  compounds  of  certain  acids  — of  which  he  mentioned 
stearic  acid  and  oleic  acid,  combined  with  glycerin. 


90 


CARBON  COMPOUNDS. 


Special  glycerides  have  received  names  terminating  in  in; 
thus  glycyl  stearate  is  called  stearin,  glycyl  palmitate  is  called 
palmitin,  glycyl  margarate  is  called  margarin. 

Distribution.  Oils  and  fats  are  produced  for  commercial  use 
from  a large  number  of  animals,  as  from  fishes  and  the  whale,  from 
hogs,  from  sheep,  and  from  beef  cattle  (and  even  horses),  also 
from  a large  number  of  different  vegetable  matters,  as  from 
olives,  the  cotton  seed,  palm  nuts,  etc. 

Preparation  of  fats.  Animal  matters,  containing  a certain 
amount  of  fat,  are  rendered ; that  is,  they  are  heated  in  a variety 
of  ways,  subjected  to  action  of  hot  water  or  steam,  or  both,  and 
the  fat  is  at  length  skimmed  from  the  other  matters. 

Tallow  oil  is  produced  by  melting  ordinary  tallow  and  then 
cooling  it  very  slowly  in  what  is  called  a seeding  room . In  this 
room  the  melted  fat  is  placed  in  wooden  cars  lined  with  zinc,  and 
the  room  is  maintained  at  a temperature  of  8o°  to  90°  F.  Little 
by  little,  the  stearin  separates  out  as  crystalline  flakes.  The  mix- 
ture of  soft  fats  and  hard  fats  is  afterward  placed  in  bags  and 
pressed.  The  softer  are  expelled  and  they  form  the  tallow  oil  of 
commerce,  chiefly  used  for  lubricating,  occasionally  for  soap. 

Lai'd  oil  is  separated  from  lard  by  a process  similar  to  that 
detailed  for  tallow  oil.  It  is  principally  used  for  lubrication. 

Bone  grease  is  used  in  inferior  soaps.  The  soap  retains  some 
color  and  a certain  offensive  odor.  The  latter  must  be  disguised 
by  scenting,  unless  the  soap  is  to  be  used  for  manufacturing  pur- 
poses. In  the  latter  case  a somewhat  offensive  odor  is  not  objec- 
tionable. 

Palm  oil  has  been  very  largely  used  in  the  manufacture  of 
soaps.  It  is  obtained  from  the  fruit  of  trees  growing  on  the  west 
coast  of  Africa,  The  fruit  is  of  about  the  size  of  a small  plum 
and  it  contains  an  outer  pulpy  mass  and  an  inner  kernel.  From 
the  pulp  is  obtained  palm  oil ; from  the  kernel  is  obtained  palm- 
nut  oil,  or  palm-kernel  oil.  The  general  process  employed  by  the 
Africans  for  obtaining  palm  oil  is  as  follows  : The  nuts  are  piled 
in  heaps,  and  then  subjected  to  a fermentation  which  goes  on 
spontaneously,  whereby  certain  of  the  constituents  soften.  Next 
they  are  thrown  into  pits  lined  with  stone,  where  they  are 
pounded  until  they  form  a pulp.  In  the  succeeding  stage  the  soft 
mass  is  put  into  water  which  is  boiled.  The  oil  rises  to  the  sur- 


FATTY  ACIDS. 


91 


face  and  is  skimmed  off.  Sometimes  this  oil  is  squeezed  through 
bags  in  order  to  accomplish  a sort  of  filtration.  The  oil  as  it 
appears  in  commerce  is  a solid  fat  of  the  consistence  of  butter. 
It  has  an  orange  or  golden  yellow  color,  although  the  color  varies 
in  different  varieties  of  oil.  The  oil  has  an  agreeable  odor  which 
the  soap  made  from  it  continues  to  afford.  The  soap  has  a color 
varying  from  yellow  to  orange  according  to  the  color  of  the  origi- 
nal oil.  Sometimes  the  oil  is  submitted  to  a chemical  bleaching. 
About  one  hundred  pounds  of  nuts  afford  about  one  gallon  of  oil. 
Many  varieties  of  palm  oil  are  brought  to  European  parts. 
While  they  are  prepared  by  different  processes,  the  operations 
are  substantially  those  already  stated. 

Cotton-seed  oil.  Each  seed  of  cotton  may  be  said  to  contain  a 
drop  of  oil.  Attempts  to  crush  cotton-seed  and  extract  oil  from 
it  were  made  in  the  State  of  Mississippi  as  early  as  1834;  that 
experiment  and  a subsequent  one  made  in  1847,  resulted  in  heavy 
pecuniary  losses.  More  successful  attempts  were  made  in  1855, 
but  the  War  of  the  Rebellion  checked  the  progress  of  the  indus- 
try. Of  late,  however,  the  business  has  progressed  until  now  it 
has  assumed  great  commercial  importance.  At  present  the  seed 
is  sold  at  a price  equalling  about  $4.00  per  bale  of  cotton.  Dur- 
ing the  season  of  1892  and  1893  seed  equivalent  to  2,500,000 
bales  of  cotton  was  crushed  ; this  must  represent  a distribution  of 
about  $10,000,000  to  cotton  planters  from  seed  alone. 

This  oil  is  employed  in  a variety  of  ways  by  bakers  and  families  for  shorten- 
ing; also  in  the  manufacture  of  soap;  as  a constituent  of  butterine ; as  a 
salad  oil;  as  a basis  for  liniments;  in  miners’  lamps  (an  Ohio  law  requires 
the  use  of  this  oil  in  mines.)  Beside  these  there  are  many  other  uses  in  trade. 
Cotton-seed  oil,  however,  is  not  satisfactory  for  household  illumination,  nor 
can  it  be  used  in  lubrication ; it  thickens  too  readily  by  oxidation  in  the  air. 

The  cotton-seed  meal,  from  which  the  oil  has  been  pressed,  is  used  as  a food 
for  cattle,  and  to  some  extent  as  a fertilizer.  The  hulls  are  often  used  as  fuel, 
the  ashes  (which  contain  a considerable  quantity  of  potassium  compounds) 
being  subsequently  employed  as  a fertilizer.  The  hulls  have  also  been  used  to 
some  extent  in  the  manufacture  of  paper. 

Blown  oils.  When  certain  oils  that  are  not  very  good  dryers, 
cotton-seed  oil  for  example,  are  subjected  to  a blast  of  air  at  a 
temperature  of  about  2000  C.,  for  several  hours,  they  undergo  a 
marked  change.  They  are  called  “ blown  ” oils.  Their  viscosity 
is  very  much  increased  and  they  are  better  fitted  for  lubricating 


92 


CARBON  COMPOUNDS. 


use,  especially  when  mixed  with  petroleum  products.  They  also 
serve  for  the  preparation  of  imitation  leather,  leatherette,  lino- 
leum, and  similar  materials. 

Bleaching  of  oils.  The  simplest  method  of  bleaching  oils 
(applicable  especially  to  the  thicker  ones,  like  palm  oil)  consists 
in  a mere  melting  which  permits  solid  matters  to  subside.  This 
process  may  be  supplemented  to  advantage  by  straining.  A sec - 
ond  method  involves  exposure  to  the  sun  in  shallow  tanks  under 
glass  windows  such  as  are  used  in  plant  houses.  A third  method 
involves  the  use  of  a current  of  steam  driven  through  the  oil.  A 
fourth  method  consists  in  blowing  air  through  the  oil  or  the  melted 
fat.  A fifth  method,  and  one  largely  used,  employs  potassium  di- 
chromate and  hydrochloric  acid.  Dichromate,  dissolved  in  a small 
amount  of  water,  is  mingled  with  the  heated  oil.  Constant  stir- 
ring is  employed.  A proper  amount  of  hydrochloric  acid  is  now 
added,  the  entire  mixture  being  again  thoroughly  agitated.  The 
chromium  compounds  produced  liberate  oxygen  which  attacks 
certain  of  the  coloring  matters  present.  Subsequently  the  mass 
is  treated  with  a large  quantity  of  water,  is  agitated  and  stirred 
again.  The  water  dissolves  the  bleaching  materials  that  have 
been  added,  but  it  allows  the  bleached  oil  to  come  to  the  surface, 
whence  it  is  drawn  off.  A sixth  method  involves  the  use  of 
liquid  chlorine.  This  substance  is  sold  in  drums,  of  course  capa- 
ble of  standing  great  pressure.  In  using  the  chlorine  a portion 
of  it  is  passed  into  water  and  this  solution  is  agitated  with  the 
oily  material.  After  the  bleaching  is  completed,  more  water  may 
be  added,  and  finally  the  oil  may  be  drawn  from  the  surface. 
Even  soap  may,  under  proper  conditions,  be  bleached  by  liquid 
chlorine. 

Uses  of  oils  and  fats.  Oils  and  fats  have  most  wide-spread  and 
important  uses  in  trade.  Briefly  stated,  their  principal  uses  are 
as  follows  : As  food  and  in  cooking  other  food  (butter,  lard,  olive 
oil,  cotton-seed  oil,  oleomargarine) ; as  soap  stock  (tallow,  cotton- 
seed oil,  olive  oil,  and  in  general,  almost  any  animal  fats) ; as  an 
illuminant,  as  candles  or  in  lamps  (lard  oil,  sperm  oil) ; as  lubri- 
cating material  (lard  oil,  sperm  oil) ; as  a filling  for  leather  (many 
inferior  kinds  of  grease,  like  fish  oils)  ; as  a source  of  glycerine 
(many  kinds  of  oil)  ; as  a material  for  use  in  paints,  oil-cloth,  etc. 
(the  drying  oils  exclusively,  as  linseed  oil). 


FATTY  ACIDS. 


93 


Stearin , or glycy l stearate , is  a hard  fat  which  is  separated  from 
the  softer  fats  (after  melting  the  mass)  by  gently  lowering  them 
in  temperature  in  a room  provided  for  the  purpose.  The  stearin 
separates  in  crystals,  while  the  soft  fats  remain  liquid.  In  due 
time  the  mixture,  being  pressed  in  cloth  bags,  allows  the  softer 
fats  to  flow  away  while  the  harder  remain  as  a white  mass  called 
stearin.  The  process  is  carried  out  on  a large  scale  in  the  manu- 
facture of  artificial  butter. 

Oleomargarine , or  butterine , consists  essentially  of  easily  melt- 
ing  fats , from  which  the  harder  fats  have  been  separated  by  a 
process  similar  to  that  just  described.  The  harder  material,  or 
stearin,  is  sold  for  the  manufacture  of  candles,  also  for  mixing 
with  lard  which  is  to  be  used  in  hot  climates ; thus  the  lard  is 
kept  at  a satisfactory  consistency.  The  oleo  oil,  after  straining 
from  the  press,  is  mixed  with  some  milk  or  cream  (to  give  it  the 
buttery  flavor)  with  some  coloring  matter  (to  impart  a yellow 
shade)  and  then,  while  still  liquid,  is  thoroughly  agitated  with 
cracked  ice.  After  the  fats  have  hardened,  a comparatively  large 
amount  of  salt  is  introduced  — this  prevents  the  sense  of  taste 
recognizing  readily  the  true  flavor  of  the  fats. 

In  natural  butter  made  from  cream,  there  exist  certain  fats  which  melt  very 
readily  at  the  temperature  of  the  mouth.  There  exist  certain  others  that  by 
reason  of  their  volatility,  afford  the  peculiar  flavor  and  odor  of  true  cows’  but- 
ter. In  making  artificial  butter,  the  effort  of  the  manufacturer  is,  first,  to  fur- 
nish a butter  that  is  soft.  Thus,  when  placed  in  the  mouth,  it  melts  easily  and 
does  not  produce  the  tallowy  impression  associated  with  those  fats  which  con- 
tain stearin.  The  essential  chemical  difference  between  artificial  butter  and  real 
butter  consists  in  the  fact  that  the  former  lacks  the  volatile  organic  acids  which 
give  to  cows’  butter  its  agreeable  flavor. 


Soap.  Soap  is  essentially  a salt  formed  by  the  union  of  some 
metallic  base  with  some  organic  fat  acid.  Ordinary  hard  soap  is 
substantially  a mixture  of  oleate,  palmitate,  and  stearate  of  sodium. 
As  a matter  of  fact,  most  laundry  soaps  contain  resin  in  the  form 
of  resinate  of  sodium.  Sometimes  adulterants  are  employed,  of 
which  sodium  silicate  may  be  mentioned.  It  is  said  that  many 
fine  toilet  soaps  contain  in  addition  sugar — sometimes  even  as 
much  as  twenty-five  per  cent. 

The  general  principles  involved  in  the  manufacture  of  soap 
may  be  presented  as  follows  : A solution  of  sodium  hydroxide  is 


94 


CARBON  COMPOUNDS. 


produced  from  that  solid  alkali  called  “caustic,”  at  present  manu- 
factured on  an  enormous  scale  (it  is  poured  while  melted  into 
iron  or  steel  drums).  In  the  soap  factory,  the  iron  is  stripped  off 
from  the  sodium  hydroxide,  and  the  solid  caustic  is  thrown  into 
the  water  in  which  it  is  to  dissolve.  Next,  fat  is  added,  and  the 
mixture  of  fat  and  alkali  is  boiled.  Decomposition  ensues, 
whereby,  in  place  of  glycyl  stearate  for  example,  sodium  stear- 
ate is  produced,  glycerin  being  liberated  and  dissolved  in  the 
water  present.  Soap  has  now  been  produced,  but  it  is  in  a liquid 
form,  that  is,  dissolved  in  water.  Common  salt  is  added  to  the 
mass,  whereupon  the  soap  separates  and  gathers  as  a kind  of  curd 
at  the  top  of  the  liquid.  The  salt  water  containing  other  impuri- 
ties is  now  drawn  away ; the  soap  then  receives  a second  boiling, 
with  more  sodium  hydroxide.  By  and  by  saponification  becomes 
complete.  Upon  allowing  the  mixture  to  stand,  a dark  colored 
liquid  settles  to  the  bottom,  and  the  soap  comes  to  the  top. 
The  latter  is  ladled  out  into  “frames”  where  it  dries  to  a suffi- 
cient extent  to  enable  it  to  assume  a solid  condition.  The  frames 
being  removed,  the  block  of  soap  is  cut,  by  means  of  wires,  into 
bars  of  suitable  size.  In  case  of  the  finer  soaps,  the  small  blocks 
first  produced  are  pressed  or  shaped  by  machinery  to  the  form 
desired. 

Marseilles  soap,  or  castile  soap , is  usually  manufactured  from 
olive  oil.  It  is  very  carefully  prepared  and  thoroughly  boiled  so 
as  to  accomplish  the  complete  saponification  of  the  oil.  The 
mottled  castile  soap  contains  an  admixture  of  ferrous  sulphide  or 
some  other  ferrous  salt.  This  substance,  upon  coming  to  the  air, 
oxidizes  and  thus  changes  from  the  green  to  the  red  color. 

Cotton  oil  soap.  Within  a few  years,  vast  quantities  of  oil  have 
been  expressed  from  cotton  seed  ; and  this  oil  is  very  largely  used 
for  the  manufacture  of  soap. 

Most  solid  soaps  contain  large  amounts  of  water.  Twenty-five  per  cent,  is 
not  an  uncommon  amount,  and  some  kinds  are  said  to  contain  as  much  as 
seventy  per  cent.  Soap,  if  thoroughly  dried,  assumes  the  form  of  a powder. 
In  this  form  — with  or  without  addition  of  dry  sodium  carbonate — it  is  very 
largely  used  as  a soap  substitute. 

2-Oxygen  Acids  of  the  Formula  CnH2n-202. 

These  acids  are  usually  designated  as  of  the  acrylic  series.  A 
great  number  of  them  are  known.  Only  one  will  be  mentioned. 


FATTY  ACIDS. 


95 


Oleic  acid,  C18H3402.  It  occurs  in  combination  with  glycyl  in 
a great  many  soft  fats,  and  to  some  extent  also  in  the  harder  fats, 
as  the  substance  called  olein. 

Olein  is  associated  with  stearin,  margarin,  and  paimitin,  in 
practically  all  the  ordinary  crude  oils  and  fats  which  are  employed 
in  the  arts.  Olein  is  discussed  here,  however  (and  not  with  pai- 
mitin, margarin,  and  stearin,)  because  oleic  acid  has  a slightly 
different  carbon  linkage  from  that  prevailing  in  the  other  com- 
mon acids  of  fats. 

2-Oxygen  Acids  of  the  Formula  C11H211-4O2. 

Linoleic  acid,  C16H2802.  This  acid  (existing  as  a glyceride  in 
linseed  oil)  is  an  oily  liquid. 

Drying  oils.  Certain  vegetable  substances  yield  fatty  oils  which  are  true 
glycerides  and  which  have  the  remarkable  power  of  absorbing  oxygen  from 
the  air  and  thus  producing  solids.  Linseed  oil  is  the  best  example.  It  is 
obtained  by  mechanical  pressure  from  the  seed  of  flax.  Its  oil  is  composed  of 
glycerin  united  with  several  special  fatty  acids,  the  principal  one  being  known 
as  linoleic  acid.  When  linseed  oil  is  spread  over  the  surface  of  wood,  paper,  or 
any  solid,  it  absorbs  oxygen  from  the  air,  forming  what  is  called  a skin.  The 
oxidation  may  go  on  gradually  and  yet  eventually  produce  a solid  mass.  In  oil 
painting,  linseed  oil  is  used;  and  the  so-called  drying  of  the  paint  is  due  to 
the  operation  just  described.  It  does  not  represent  any  evaporation  like  that 
taking  place  when  water  colors  are  applied  to  paper.  It  represents,  instead,  an 
absorption  of  something  from  the  air,  namely,  oxygen.  If  linseed  oil  in  a tank 
is  subjected  to  a current  of  air  forced  through  it,  it  is  easily  shown  that  oxida- 
tion goes  on,  by  the  subsequent  analysis  of  the  product  and  by  the  fact  that  the 
original  oil  rises  in  temperature  and  increases  in  weight.  It  also  becomes 
very  thick  and  pasty,  producing  a quantity  of  gum  that  may  be  employed  in 
many  ways  in  the  arts. 

Linseed  oil  is  often  boiled  with  certain  compounds  of  lead,  in  which  case  a 
quantity  of  soap  is  formed  which  may  be  called  lead  linoleate.  If  red  lead  is 
used  in  the  boiling  operation,  the  oxygen  of  this  highly  oxidized  compound 
assists  in  the  oxidation  of  the  oil. 

In  order  to  make  oil  paint  spread  easier,  it  is  often  thinned  with  certain  solv- 
ents like  turpentine  or  petroleum  naphtha.  When  such  thinned  {liquids  are 
employed  for  painting  purposes,  of  course  the  volatile  solvent  evaporates,  leav- 
ing a thin  layer  of  the  thicker  oil  behind. 

3-Oxygen  Acids  of  the  Formula  CnH2nC>3. 

Carbonic  acid,  CH203,  or  HOOC'OH.  This  acid  has  a theo- 
retical rather  than  an  actual  existence.  Its  formula  is  deduced 
from  those  of  its  salts.  Its  anhydride,  carbon  dioxide,  C02,  is 


96 


CARBON  COMPOUNDS. 


well  known ; it  is  usually  discussed  with  the  compounds  of  the 
non-metals.  The  acid  is  mentioned  here  mainly  for  purposes  of 
classification. 

Gly collie  acid,  C2H403,  or  HOOC*CH2OH.  This  acid  is  pro- 
duced by  oxidation  of  glycol,  ethylene  alcohol,  C2H4(OH)2,  some- 
what as  acetic  acid  is  produced  by  oxidation  of  ethyl  alcohol, 
C2H5OH. 

The  acid  is  a crystalline  solid. 

Lactic  acid , C3H603,  or  HOOC*CHOH’CH3.  This  is  the  acid 
of  sour  milk.  It  may  be  formed,  however,  from  a number  of 
other  substances.  Thus  the  proper  fermentation  of  starch  and  of 
glucose  gives  rise  to  it.  It  also  exists,  in  some  forms  of  dyspep- 
sia, in  the  gastric  juice.  It  is  produced  by  the  souring  of  certain 
vegetables.  Lactic  acid  appears  to  be  the  product  of  a specific 
fermentation  called  the  lactic  fermentation,  and  this  fermentation 
is  carried  on  under  the  influence  of  a special  microbe  called  bac- 
terium acidi  lactici.  A special  method  has  lately  been  invented 
for  producing  a pure  culture  of  the  lactic  ferment,  then  allowing 
it  to  act  upon  glucose  made  from  corn  starch.  There  is  thus  pro- 
duced a lactic  acid  comparatively  free  from  by-products. 

It  has  been  proposed  to  use  such  lactic  acid  in  some  processes  of  dyeing  of 
textile  fabrics  as  a substitute  for  certain  other  organic  acids,  notably  oxalic  and 
tartaric  acids. 

Lactic  acid,  lactates,  and  many  other  derivatives  of  lactic  acid,  have  been 
carefully  studied  for  the  purposes  of  theoretical  chemistry. 


3-Oxygen  Acids  of  the  Formula  C11H2P.-2O3. 

Ricinoleic  acid , Ci8H3403.  This  substance  occurs  in  combina- 
tion in  castor  oil  and  some  other  oils.  Like  other  fatty  sub- 
stances, it  exists  here  as  a glyceride. 

Ricinoleic  acid  of  castor  oil  forms  with  sulphuric  acid  a sul- 
phonic  acid.  This  substance  is  considerably  used  in  dyeing  and 
calico  printing,  particularly  in  connection  with  alizarin.  It  is 
often  called  “alizarin  assistant.”  With  the  aluminous  mordants, 
it  seems  to  form  favorable  compounds  from  which  the  alizarin 
can  subsequently  withdraw  the  alumina  so  as  to  produce  the 
desired  red  color  upon  cloth. 


FATTY  ACIDS. 


97 


4-Oxygen  Acids  of  the  Formula  CnH2n-204. 

Oxalic  acid,  C2H204,  or  (HOOC)2,  occurs  in  nature  in  certain 
plants  ; as  for  example,  in  sorrel,  oxalis  acetosella. 

Oxalic  acid  may  be  manufactured  by  the  action  of  nitric  acid 
upon  sugar. 

This  acid  is  now  produced  on  a large  scale  from  sawdust  of  cer- 
tain kinds,  especially  pine,  by  heating  it  with  solid  potassium 
hydroxide.  (Sodium  hydroxide  alone  will  not  accomplish  the 
change.) 

Oxalic  acid  readily  forms  white  crystals  containing  two  mole- 
cules of  water.  It  is  a strong  acid,  compared  with  other  organic 
acids ; in  considerable  quantities,  it  is  very  poisonous. 

Oxalic  acid  is  largely  used  in  certain  textile  industries;  as  in  calico  printing 
and  in  wool  dyeing.  Here  it  is  strong  enough  to  accomplish  the  decomposi- 
tion as  desired ; but  it  does  not,  like  the  inorganic  acids,  injure  the  fibre  to 
which  it  is  applied. 

Oxalic  acid  forms  a large  number  of  salts,  some  of  them  considerably  used  in 
the  arts.  Calcium  oxalate  is  a white  substance,  insoluble  in  water.  It  is  in 
this  form  that  calcium  is  ordinarily  precipitated  in  chemical  analysis. 

A7nmonium  oxalate , a white  crystalline  salt,  soluble  in  water,  is  largely  used 
in  chemical  analysis  for  the  recognition  of  calcium  by  the  method  already  sug- 
gested. 

Malonic  acid,  C3H404,  or  HOOC’CHyCOOH.  This  is  a color- 
less crystalline  solid. 

Succinic  acid,  C4H604,  or  HOOC,CH2,CH2*COOH.  Succinic 
acid  was  originally  obtained  by  the  distillation  of  amber.  It  has 
since  been  learned  that  it  may  be  produced  from  certain  varieties 
of  lignite.  It  is  said  to  exist  also  in  lettuce  and  certain  other 
vegetables.  It  has  often  been  reported  as  existing  in  unripe 
grapes. 

At  present  it  is  well  recognized  that  succinic  acid  may  be  pro- 
duced by  certain  purely  chemical  transformations,  and  also  by 
certain  fermentations  under  the  influence  of  a special  and  appro- 
priate microbe.  Thus,  malic  acid,  the  acid  of  certain  other  fruits 
beside  the  apple,  may  afford  succinic  acid  by  an  appropriate  fer- 
mentation. This  is  not  difficult  to  comprehend  chemically, 
because  malic  acid  is  oxysuccinic  acid. 

Succinic  acid  forms  many  succinates  ; as  ammonium  succinate,  which  forms 
transparent  crystals  soluble  in  water  and  which  is  used  somewhat  in  chemical 
operations.  Thus,  it  is  employed  occasionally  in  the  precipitation  of  iron.  It 
then  forms  a ferric  succinate  which  is  a gelatinous  precipitate.  * 

7 


98 


CARBON  COMPOUNDS . 


4- Oxygen  Acids  of  the  Formula  Cnhbn-^O*. 

Fumaric  acid , C4H4O4,  or  HOOOCH 

HC-COOH 

Maleic  acid , C4H4O4,  or  HOOOCH 

HOOC-CH 

Both  of  these  acids  are  produced  by  the  dry  distillation  of 
malic  acid,  C4H605.  They  have  different  chemical  properties, 
although  they  have  the  same  empirical  formula.  They  are 
believed  to  be  geometrical  isomers  ; that  is  in  the  two  cases 
the  carboxyl  groups  are  distributed  on  different  sides  of  the 
doubly  linked  carbon  atoms,  an  arrangement  that  is  partly  sug- 
gested by  the  formulas  printed  above,  but  is  better  displayed 
when  these  carbon  atoms  are  represented  by  tetrahedrons. 

5- Oxygen  Acids  of  the  Formula  CnH2n-  205. 

Malic  acid. \ C4H605,  or  HOOC,CH2*CHOH,COOH.  Malic 
acid  has  long  been  recognized  as  existing  in  certain  sour  fruits ; 
as,  pears,  apples,  gooseberries,  barberries,  and  many  others. 

Malic  acid  is  generally  prepared  from  the  berries  of  the  moun- 
tain ash.  It  is  not  much  employed  in  chemistry,  although  it 
forms  many  malates  and  substitution  compounds. 

6- Oxygen  Acids  of  the  Formula  CnHhn^Og. 

Tartaric  acid , C4H606,  or  HOOC'CHOHCHOH'COOH. 

This  substance  is  properly  the  acid  of  grapes.  It  appears  to 
exist  in  grape  juice  in  the  form  of  an  acid  potassium  tartrate. 
While  the  source  just  mentioned  is  the  chief  one  employed  in  the 
production  of  the  tartaric  acid  required  in  the  arts,  this  acid  is 
found  in  many  other  plants. 

It  is  worthy  of  note  at  the  outset  that  there  appear  to  be  four 
kinds  of  tartaric  acid,  all  having  the  same  empirical  formula. 

First,  ordinary,  or  dextrotartaric  acid.  Aqueous  solution  of  this  acid  has  the 
power  of  turning  the  plane  of  the  polarized  ray  to  the  right. 

Second,  laevotartaric  acid.  This  substance,  when  in  aqueous  solution,  has 
the  power  of  turning  the  plane  of  the  polarized  ray  to  the  left. 

Third,  racemic  acid.  This  acid  is  optically  inactive.  It  is  produced  when 
equal  quantities  of  the  dextro-  and  the  laevo-  acids  are  dissolved  in  water, 
brought  together,  and  then  crystallized.  Racemic  acid  may  afterward  be 
resolved  into  the  two  optically  active  tartaric  acids. 

Fourth,  mesotartaric  acid.  This  is  optically  inactive. 


FATTY  ACIDS. 


99 


The  peculiarities  of  tartaric  acid  have  been  carefully  studied,  first  by  Louis 
Pasteur,  many  years  ago,  since  by  others.  At  present  the  differences  are 
considered  as  due  to  geometrical  isomerism  and  they  are  explained  on  the  basis 
of  the  modern  theories  of  stereo-chemistry.  This  involves  the  idea  that  the 
carbon  atom  may  have  its  four  points  of  attraction  not  in  one  plane  but  at  four 
points  corresponding  to  the  apexes  of  a tetrahedron.  Then  two  or  more  atoms 
of  carbon  may  be  connected  by  apexes  or  by  edges  of  the  imagined  tetrahedron. 
Then  radicles  attached  at  the  other  solid  angles  of  the  tetrahedron  may  be  dis- 
posed differently  in  space.  In  case  of  asymmetric  carbon  atoms  the  attached 
radicles  may  have  clearly  two  different  relative  positions  differing  somewhat  as 
the  parts  of  a real  object  differ  in  position  as  compared  with  these  parts  as  they 
appear  when  reflected  in  a mirror. 

The  different  varieties  of  tartaric  acid  are  capable  of  forming 
different  tartrates  as  well  as  racemates. 

In  the  course  of  the  fermentation  of  wine,  the  generation  of 
alcohol  by  decomposition  of  sugar  forms  a solution  that  tends  to 
precipitate  certain  of  the  tartrates.  At  the  bottom  of  wine  casks 
a sediment  forms.  It  is  called  argols  or  wine  lees,  or  crude  tar- 
tar. It  consists  chiefly  of  acid  potassium  tartrate,  but  it  also 
often  contains  calcium  tartrate.  From  this  material  is  manufac- 
tured tartaric  acid  and  the  various  tartrates  used  in  medicine  and 
in  the  arts. 

Tartaric  acid  may  be  produced  by  acting  upon  the  crude  tartar 
with  chalk ; thereby  calcium  tartrate  is  precipitated.  This  pre- 
cipitate is  subsequently  decomposed  by  sulphuric  acid,  thus  form- 
ing calcium  sulphate  and  liberating  tartaric  acid.  The  latter 
substance  separates  in  crystals  when  the  clear  liquid  containing 
it  is  allowed  to  cool.  Tartaric  acid  has  also  been  produced  syn- 
thetically. 

Tartaric  acid  is  easily  decomposed  by  heat  and  by  many  chemi- 
cal reagents.  Thus  it  may  be  broken  up  into  various  modified 
forms  of  tartaric  acid  : it  may  produce  acetic  acid,  formic  acid, 
carbonic  acid,  and  several  other  substances. 

Tartaric  acid  or  its  salts  are  considerably  used  in  medicine. 
The  acid  is  largely  used  in  dyeing  and  calico  printing.  Refer- 
ence has  already  been  made  to  its  use  in  calico  printing  for 
decomposing  yellow  prussiate  of  potash,  thus  forming  Prussian 
blue  upon  the  cloth.  In  dyeing  certain  scarlets  upon  wool,  tar- 
taric acid  or  acid  potassium  tartrate  is  often  employed ; and 
while  other  acids  may  be  used  in  its  stead,  they  do  not  fully 
replace  it. 


100 


CARBON  COMPOUNDS. 


Two  of  the  most  important  salts  of  tartaric  acid  are  the  acid 
potassium  tartrate  called  cream  of  tartar,  and  the  potassioantimo- 
nylic  tartrate  called  tartar  emetic. 

Cream  of  tartar.  This  substance  is  very  largely  employed  in  the  United 
States  and  Canada  in  the  production  of  baking  powders.  Practically  speaking, 
baking  powders  are  mixtures  of  three  dry  substances.  The  first  is  a dry  acid 
compound.  It  may  be  cream  of  tartar  or  an  acid  phosphate.  The  second  sub- 
stance is  hydrosodium  carbonate.  The  third  substance  is  flour  or  starch. 
While  these  three  substances  are  dry,  no  chemical  reaction  takes  place.  As 
soon,  however,  as  they  are  brought  in  contact  with  water,  the  first  two  dissolve 
and  the  starch  softens.  The  first  two  react  in  such  a way  as  to  liberate  a large 
volume  of  carbonic  gas.  If  the  operation  takes  place  in  presence  of  an  ample 
supply  of  wheat  flour  or  similar  material,  the  paste  so  produced  is  inflated  by  a 
multitude  of  little  bubbles  of  carbonic  gas.  If  this  paste  is  quickly  heated  in  an 
oven,  that  is,  baked,  the  cell  walls  are  thereby  hardened.  Thus,  what  is  called 
light  bread  is  produced.  It  may  be  noted  that  in  the  fermentation  of  bread  by 
means  of  yeast  or  leaven,  the  starch  or  flour,  under  the  influence  of  the  yeast 
microbe,  undergoes  decomposition  into  carbon  dioxide  and  alcohol.  The  libera- 
tion of  carbon  dioxide  in  minute  portions  throughout  the  dough  or  other  paste 
accomplishes  an  inflation  similar  to  that  which  is  produced  by  the  baking  pow- 
ders as  just  described.  With  baking  powders  the  inflation  is  quicker.  It  must 
be  remembered,  however,  that  the  baking  powders  leave  in  the  bread  certain 
salts  which  were  formed  at  the  time  of  the  liberation  of  the  carbonic  gas. 

Tartar  emetic , in  doses  of  a few  milligrammes,  has  medical  effect;  in 
slightly  larger  doses,  it  acts  as  an  emetic;  while,  if  the  dose  is  still  further 
increased,  it  acts  as  a poison,  sometimes  with  fatal  results. 

Citric  acid,  C6H8Ot,  or  (HOOC)CH2-(HOOC)COH-(HOOC)CH  2 

HOOOCH2 

HOOC-COH 

I 

hooc-ch2 

This  substance  is  that  which  imparts  the  sour  taste  to  lemons, 
limes,  and  certain  other  fruits.  In  the  currant,  raspberry,  straw- 
berry, cherry,  and  other  fruits,  citric  acid  exists*  together  with 
malic  acid. 

Citric  acid  is  manufactured  in  the  form  of  a syrup  and  also  in 
the  form  of  transparent  colorless  crystals.  It  is  produced  in 
Sicily  and  the  West  Indies.  The  juice  of  the  lemon,  for  example, 
being  pressed  out  of  the  fruit,  is  first  precipitated  by  the  use  of 
powdered  chalk.  Calcium  citrate  is  formed  and  precipitated. 


FATTY  ACIDS. 


IOI 


After  this  salt  has  been  washed,  it  is  decomposed  by  sulphuric 
acid  which  combines  with  the  calcium,  forming  an  insoluble  cal- 
cium sulphate,  and  at  the  same  time  liberates  the  citric  acid.  The 
latter  substance  may  then  be  separated  in  crystals  by  evaporation 
or  cooling  or  the  two  combined. 

Like  several  other  organic  substances  commonly  found  in  ani- 
mals and  plants,  citric  acid  has  been  produced  synthetically. 

Citric  acid  forms  many  citrates,  some  of  them  used  in  medicine.  Citric  acid 
is  considerably  used  in  calico  printing  where  a substance  having  mild  acid 
properties  is  desired,  but  one  which  will  not  injure  the  goods.  It  is  often 
printed  on  calico  in  the  form  of  a paste,  as  what  is  called  a “ resist.”  At  the 
points  on  the  cloth  where  the  citric  acid  is,  the  dyeing  materials  subsequently 
applied  produce  no  color,  owing  to  the  action  of  the  acid.  By  this  means, 
white  spaces  may  be  left  where  the  pattern  demands  it. 


CHAPTER  XIII. 


ALDEHYDES  AND  KETONES. 

Aldehydes  have  the  general  formula,  R'COH,  while  ketones 
have  the  general  formula,  RCO'R.  Thus  an  aldehyde  is  a 
ketone  in  which  one  of  the  alkyl  radicles  has  been  replaced  by 
hydrogen ; or  a ketone  in  an  aldehyde  in  which  the  principal 
atom  of  hydrogen  has  been  replaced  by  an  alkyl  radicle. 

Aldehydes. 

Many  aldehydes  are  known.  They  are  generally  formed  by 
oxidation  of  corresponding  alcohols.  They  are  also  formed  by 
decomposition  (under  the  influence  of  heat,  with  special  condi- 
tions,) of  certain  salts  of  organic  acids. 

Most  of  the  aldehydes  are  volatile  liquids. 

Among  the  general  chemical  properties  of  aldehydes  are  the  following : 

1.  They  are  easily  oxidized  into  organic  acids. 

2.  They  are  powerful  reducing  agents  ; thus  when  added  to  certain  solutions 
of  silver  salts  they  reduce  the  salts,  precipitating  the  metallic  silver  in  such  a 
form  that  it  forms  a lustrous  mirror  on  the  inside  of  the  glass  vessel  in  which 
the  operation  is  conducted. 

3.  Some  of  them  form  solid  crystalline  compounds  with  ammonia. 

Formic  aldehyde  (called  formalin)  CH20,  or  H‘CO'H.  This 
substance  is  produced  by  oxidation  of  methyl  alcohol.  The 
method  employed  is  to  conduct  a mixture  of  air  and  vapor  of 
methyl  alcohol  over  moderately  heated  platinum  (either  in  the 
form  of  wire  or  sponge).  The  platinum  determines  an  oxidation  : 


2CH30H 

4-  02  = 

2H-CO-H 

-f-  2H2O 

Methyl 

Oxygen 

Formic 

Water 

alcohol 

aldehyde 

The  substance  is  a volatile  liquid. 

A water  solution  of  it  is  used  in  physiological  laboratories  for 
preserving  and  hardening  animal  tissues  (it  coagulates  albuminous 
matters). 

It  is  somewhat  used  as  a disinfectant. 

(102) 


ALDEHYDES  AND  KETONES . 


103 


Acetic  aldehyde  (ordinary  aldehyde)  C2H40,  or  CHyCOH. 
This  substance  is  produced  by  the  oxidation  of  ethyl  alcohol. 
When  vapor  of  ethyl  alcohol  mixed  with  air  comes  in  contact 
with  platinum  sponge  the  alcohol  is  oxidized  into  aldehyde  as 
well  as  into  acetic  acid  (the  latter  represents  a more  considerable 
oxidation).  Indeed,  in  making  acetic  acid  from  alcohol  by  such  a 
process,  care  must  be  taken  that  aldehyde  is  not  formed  — it 
would  occasion  waste. 

Aldehyde  is  also  formed  when  ethyl  alcohol  is  oxidized  by 
potassium  dichromate  and  sulphuric  acid  (a  much-used  oxidizing 
mixture). 

2C2H5OH  + 02  >' = 2CH3-COH  + 2H20 

Ethyl  Oxygen  Acetic  Water 

alcohol  aldehyde 


Acetic  aldehyde  is  a colorless,  volatile  liquid,  having  a peculiar, 
etherial  odor.  (Inhalation  of  a considerable  quantity  of  the  vapor 
is  injurious.) 


Chloral , C2HCI3O,  or  CCls’CO'H.  Just  as  the  oxidation  of  alcohol  produces 
aldehyde,  so  its  powerful  chlorination  produces  chloral.  A comparison  of  the 
formulas  of  aldehyde  and  chloral  shows  that  the  former  corresponds  closely 
with  the  latter,  except  that  in  the  latter  three  atoms  of  chlorine  take  the  place 
of  three  of  the  atoms  of  hydrogen  in  the  other. 

The  well  known  form  of  chloral  is  the  hydrate,  C2HCI3OH2O,  a substance 
much  used  for  inducing  sleep.  This  effect  of  chloral  hydrate  is  believed  to  be 
due  to  its  change  into  chloroform  in  the  animal  system.  Artificially,  the  altera- 
tion into  chloroform  may  be  produced  by  addition  of  an  alkali.  Thus, 

C2HC130  -h  KOH  = CHClg  + KOOC-H 
Chloral  Chloroform  Potassium 

formate 


Ketones. 

The  general  formula  of  the  ketones,  R‘COR,  at  once  suggests 
the  possibility  of  two  classes  existing,  (i)  When  the  two  alkyl 
radicles  are  alike  the  ketone  is  called  simple.  (2)  When  the  two 
alkyl  radicles  are  different  the  ketone  is  called  mixed.  Thus 
dimethyl  ketone  (ordinary  acetone)  CH3COCH3,  is  a simple 
ketone;  methyl  ethyl  ketone,  CH3,CO'C2H5,  is  a mixed  ketone. 


Ketones  are  produced  from  salts  of  organic  acids  and  from  alcohols. 

Thus  destructive  distillation  of  calcium  acetate  yields  a ketone,  dimethyl 
ketone,  ordinary  acetone,  CH3*COCH3: 


104 


CARBON  COMPOUNDS. 


Ca(OOC*CH3)2  heated 


ch3-coch3 


+ CaC03 


Calcium 

acetate 


Dimethyl 

ketone 


Calcium 

carbonate 


Oxidation  of  secondary  alcohols  yields  ketones  : 

2(CH3-CHOH-CH3)  + 02  = 2(CH3-CO-CH3)  + 2h2o 

Secondary 
propyl  alcohol 

The  ketones  with  smaller  numbers  of  carbon  atoms  are  vola- 
tile liquids,  those  with  higher  numbers  are  crystalline  solids. 

Acetone , dimethyl  ketone , C2H60,  or  CH3,CO’CH3.  This  sub- 
stance is  a volatile  liquid,  having  a peculiar  odor. 

It  is  prepared  by  the  dry  distillation  of  metallic  acetates,  as 
barium  or  calcium  or  lead  acetate.  It  is  also  produced  (along 
with  methyl  alcohol,  acetic  acid,  and  other  compounds,)  when 
wood,  sugar,  starch,  gums,  and  other  similar  substances,  are  sub- 
jected to  the  process  of  dry  distillation,  with  or  without  lime. 

Acetone  is  somewhat  used  in  the  arts  as  a solvent. 


CHAPTER  XIV. 


CARBOHYDRATES. 

Introduction. 

Sugar,  starch,  cellulose  (woody  fibre),  and  gums  are  somewhat 
typical  substances.  They  represent  a numerous  and  important 
class  of  bodies  whose  representatives  are  very  widely  distributed 
through  vegetable  matters  (and  to  a far  less  extent  in  animal  mat- 
ters). These  substances  are  compounds  of  carbon,  hydrogen,  and 
oxygen ; and  in  many  cases  the  hydrogen  and  oxygen  are  in  the 
proper  ratio  to  form  water.  These  substances  have  been  called 
carbohydrates.  But  they  are  not  hydrates  of  carbon  ; they  are 
not  compounds  of  carbon  and  water ; indeed  there  are  members 
of  the  group,  recently  discovered,  in  which  the  hydrogen  atoms 
bear  to  the  oxygen  atoms  other  ratios  than  2:1.  However,  they 
are  still  called  carbohydrates  for  convenience.  (Of  course  they 
must  be  carefully  distinguished  from  hydrocarbons.) 

All  the  indications  lead  to  the  belief  that  the  carbohydrates  are 
open  chain  compounds.  The  prevalence  in  carbohydrates  of  the 
group  C6  which  is  characteristic  of  aromatic  compounds,  and  also 
the  fact  that  benzene,  C6H6,  the  typical  aromatic  compound,  is 
easily  derived  from  cellulose  and  from  bituminous  coal  (itself  dis- 
tinctly derived  from  cellulose)  point  to  some  intimate  relation- 
ship between  carbohydrates  and  aromatic  compounds. 

In  the  majority  of  cases  the  molecular  structure  characterizing  carbohydrates 
has  not  been  satisfactorily  made  out;  but  within  recent  years  several  European 
chemists,  notably  Emil  Fischer  and  B.  Tollens,  have  made  very  great  progress 
in  this  line.  But  there  is  still  much  doubt  not  only  as  to  the  proper  rational 
formulas  for  carbohydrates,  but  even  as  to  the  exact  empirical  formulas. 

Again,  the  correct  arrangement  and  classification  of  these  substances  is  uncer- 
tain. Many  systems  of  naming  have  been  proposed,  but  as  these  depend  upon 
different  theories  of  the  composition  and  relationships  of  the  bodies  under  dis- 
cussion, no  system  of  naming  even  has  gained  general  acceptance. 

Some  of  the  reasons  why  the  formulas  of  carbohydrates  are  not  absolutely 
determined  are  the  following : 

0°5) 


io6 


CARBON  COMPOUNDS. 


1.  Practically  all  of  them  are  solids,  not  capable  of  assuming  the  gaseous 
state  without  decomposition.  (But  the  gaseous  form  of  a compound  is  almost 
the  only  one  that  reveals  its  molecular  weight.) 

2.  The  fact  that  they  are  solids  suggests  that  they  have  large  numbers  of 
atoms  in  the  molecule.  (Of  course  this  gives  opportunities  for  many  isomers 
and  so  creates  uncertainty  in  a particular  case.) 

3.  They  are  rather  neutral  in  their  chemical  relations.  (Now  substances 
that  do  not  readily  form  substitution  compounds  and  the  like,  offer  special 
difficulties  in  the  way  of  fixing  of  their  structures.) 

4.  When  a given  carbohydrate  is  decomposed  by  heat  or  other  agencies,  it 
generally  produces  a great  many  different  products,  and  some  of  these  are  diffi- 
cult of  identification.  (These  facts  operate  somewhat  like  those  already  men- 
tioned.) 

5.  It  is  by  no  means  easy  to  build  up  carbohydrates  synthetically ; most  of 
them  are  products  of  growing  plants,  and  while  in  the  plant,  they  appear  to  be 
produced  by  simple  operations  (that  is,  carbon  dioxide  of  the  air  or  of  the  soil, 
and  water,  form  certain  sugars,  and  these  produce  starches,  gums,  and  woody 
fibre,)  yet  the  plant  physiology  of  the  carbohydrates  is  not  easy  to  fathom. 

It  must  be  stated,  however,  that  in  recent  years  a large  number  of  sugar-like 
carbohydrates  have  been  made  artificially. 

First  Group.  The  Sugars. 

1.  The  sugars  are  widely  distributed  in  plants;  most  sweet 
fruits  and  sweet  vegetable  juices  contain  one  or  more  kinds  of 
sugar;  so  do  some  animal  products,  as  milk,  which  contains  milk- 
sugar  or  lactose.  (Of  course  honey  is  a vegetable  product,  for 
the  honey  bee  merely  collects  the  sweets  from  flowers.) 

2.  Sugars  are  ordinarily  prepared  by  extracting  the  juice  from 
the  plant  (as  in  squeezing  sugar  cane)  and  then  purifying  and 
evaporating  the  juice.  But  some  sugars  are  prepared  chemically 
from  other  products. 

3.  The  sugars  are  sweet  in  taste,  but  some  are  sweeter  than 
others ; thus  cane  sugar  is  sweeter  than  milk  sugar.  (The  arti- 
ficial aromatic  compound  saccharine , 500  times  as  sweet  as  cane 
sugar,  belongs,  however,  to  an  entirely  different  class.) 

4.  Most  of  the  sugars,  when  in  solution,  rotate  the  plane  of 
the  ray  of  polarized  light ; those  which  turn  it  to  the  right  are 
designated  as  d (dextro)  — to  the  left,  1 (laevo)  — the  optically 
inactive  ones,  i. 

5.  Many  sugars  have  a marked  effect  on  Fehling’s  solution. 
This  solution  is  essentially  cupric  sulphate  acidified  by  tartaric 
acid  and  then  rendered  strongly  alkaline  with  sodium  hydroxide. 


CARBOHYDRATES ; SUGARS. 


10  7 


(Addition  of  sodium  hydroxide  to  copper  compounds  usually  gives 
rise  to  a precipitate  of  copper  hydroxide.  Tartaric  acid  and  cer- 
tain other  organic  substances  have  the  power  of  preventing  this 
precipitation,  so  that  in  this  case,  the  sodium  hydroxide,  instead 
of  precipitating  the  copper,  dissolves  it  to  a deep  blue  liquid.) 
The  action  of  certain  sugars  upon  Fehling’s  liquid  is  to  withdraw 
oxygen  from  the  copper  compound  and  to  produce  a brick  red 
precipitate  of  cuprous  oxide,  Cu20.  If  a sufficient  amount  of 
the  sugar  is  employed,  all  of  the  copper  may  be  thrown  out  of  the 
liquid  in  this  way. 

6.  In  many  cases  caustic  alkalies  turn  sugars  and  other  car- 
bohydrates to  brown  colored  compounds. 

j.  Acids  decompose  sugars  — dilute  acids  often  produce  what 
is  called  invert  sugar.  Concentrated  nitric  acid  often  produces 
saccharic  acid  and  mucic  acid,  and  eventually  even  oxalic  acid. 

8.  Yeasts  act  upon  some  sugars  and  not  upon  others. 

9.  Phenyl  hydrazine,  NH  (C6H5)*NH2,  is  one  of  the  most 
important  of  reagents  as  respects  carbohydrates. 

The  substance  called  hydrazine,  NH2.NH2,  may  form  certain 
substitution  compounds ; one  of  these  is  phenyl  hydrazine, 
NH(C6H5)-NH2,  or  NHPh-NH2. 

When  phenyl  hydrazine  acts  on  aldehydes  and  on  ketones  it 
forms  certain  reduction  products  called  hydrazones,  thus  : 

Acetaldehyde  hydrazone  is  NHPh-N  : CH*CH3 
Acetone  hydrazone  is  NHPlvN  : C(CH3)2 

But  phenyl  hydrazine  also  yields  hydrazones  with  sugars  ; the 
hydrazones  may  be  changed  to  osazones  (generally  rather  insolu- 
ble in  water)  ; thence  to  osones,  which  by  nascent  hydrogen  may 
yield  sugars,  different  it  may  be  from  the  sugar  used  at  the  out- 
set. 

Conspectus  of  Sugars. 

Triose.  C3H0O3.  Glycerose.  (Artificial.)  Prepared  by  oxidizing  action  of 
bromine  in  presence  of  sodium  carbonate  on  glycerol,  C3H803. 

Tetrose.  C4H804.  Erythrose.  (Artificial.)  Prepared  by  oxidizing  action  on 
erythrol,  C4H10O4. 

Pentoses.  C5H10O5.  Arabinose.  (Artificial.)  Prepared  from  certain  gum 
arabics  by  action  of  dilute  sulphuric  acid.  — Xylose.  Prepared 
from  certain  vegetable  gums  by  action  of  concentrated  sulphuric 
acid. 


io  8 


CARBON  COMPOUNDS. 


Hexoses.  C6H12Oe.  (Many  are  artificial.)  a-Acrose.  Prepared  from  for- 
mic aldehyde,  CH20,  by  action  of  magnesium  oxide  and  sul- 
phate with  granulated  lead. — Formose.  Also  prepared  from  formic 
aldehyde. — Galactose,  d,  1,  i.  Prepared  from  milk-sugar  and  other 
substances  by  various  methods. — Glucose,  d,  1,  i.  d occurs  in 
many  sweet  fruits.  It  is  made  artificially  from  starch  by  action  of 
dilute  sulphuric  acid  and  otherwise. — Gulose.  Artificial. — Dam- 
bose.  Occurs  in  certain  muscular  tissues  of  animals. — Fruc- 
tose. Occurs  widely  distributed  in  fruits. — Mannose,  d,  1,  i. 
d occurs  in  certain  nuts. — Phenose.  Prepared  from  certain  aro- 
matic compounds  of  phenyl  hydride,  CeHs-H. — Sorbose.  Prepared 
by  fermentation  of  the  juice  of  berries  of  mountain  ash,  sorbus. — 
Rhamno-hexose. — (Many  others.) 

Heptoses.  C7H14O7.  Gluco-heptose.  Artificial. — Manno-heptose.  Artificial. — 
Rhamno-heptose.  Artificial. — (Many  others.) 

Octoses.  C8H1608.  Gluco-octose.  Artificial. — Manno-octose.  Artificial. 

Nonoses.  CgH1809.  Glttco-nonose.  Artificial. — Manno-nonose.  Artificial. 


. Ci2H22Oh.  Maltose.  Produced  by  action  of  malt  upon  starch  (and 
otherwise). — Lactose,  milk  sugar.  Exists  in  the  milk  of  mammals 
and  elsewhere). — Sucrose , cane  sugar.  Exists  in  juice  of  sugar 
cane,  sugar  beet,  sugar  maple,  sugar  palm,  and  in  the  nectar  of 
flowers  (in  honey)  and  elsewhere.  Usually  it  is  found  in  nature 
mixed  with  other  sugars,  etc. — (Several  others.) 


• C6Hi205,  Ci8H320i6-2H20,  Ci8H320i6,5H20.  These  formulas  present 

suggestions  of  many  other  sugars  of  different  type  from  those 
above  referred  to. 

Glucose,  CeHiaOe  (d,  1,  i.) 

This  is  the  substance  called  dextrose,  grape-sugar,  starch- 
sugar. 

The  formula  is  supposed  to  be  one  of  the  three  following  : 


H 

H 

H 

HC— OH 

HC— OH 

HC— OH 

HC— OH 

HC— OH 

HC— OH 

HC— OH 

HC— OH 

HC— OH 

1 

HC— OH 

HC— OH 

1 

C = 0 

HC— OH 

C = 0 

| 

HC— OH 

| 

HC  = O 

| 

HC— OH 

HC— OH 

H 

H 

CARB OHYDRA  TES  ; S UGA  RS. 


109 


Glucose  is  widely  distributed  in  nature  in  sweet  fruits.  It 
exists  also  in  honey.  In  certain  morbid  animal  processes,  it  is 
produced  and  excreted.  In  human  beings  this  occurs  in  the  dis- 
ease called  diabetes  inellitus. 

Glucose  may  be  produced  artificially  by  the  action  of  certain 
dilute  acids  upon  starch.  In  some  parts  of  the  United  States 
the  manufacture  of  such  glucose  is  an  important  industry.  Corn 
starch  is  heated  gently  with  sulphuric  acid  until  the  chemical 
change  has  been  accomplished.  The  excess  of  sulphuric  acid  is 
then  removed  by  the  addition  of  lime.  Calcium  sulphate  is  pro- 
duced and  appears  as  an  abundant  white  precipitate.  The  pasty 
mass  being  strained  in  filter  presses,  affords  a clear  syrup  con- 
taining the  glucose.  This  syrup  may  be  partly  or  wholly  evapo- 
rated in  suitable  vacuum  pans.  If  wholly  evaporated,  it  leaves  a 
white  solid  known  in  the  trade  as  glucose.  This  material  is 
largely  used  as  a substitute  for  cane  sugar,  and  occasionally  as  an 
adulterant  for  it.  It  cheaply  replaces  cane  sugar  in  an  enormous 
quantity  of  candies.  Owing  to  its  capacity  for  fermentation,  it  is 
also  employed  in  the  manufacture  of  beer  and  ale: 

In  the  form  of  a syrup,  it  is  largely  used  as  a substitute  for 
sweetening  liquids  such  as  molasses,  maple  syrup,  and  sugar 
house  syrup. 

Glucose  is  produced  by  the  decomposition  of  many  other  sugars  : thus  cane 
sugar  is  decomposed  by  dilute  acids  : 


C12H22O11  + H2O 
Cane  sugar 


C6H12O6  -f-  C6H12O6 
Glucose  Laevulose 


Glucose  is  a reducing  agent.  It  reduces  cupric  oxide  in  Fehling’s  solution  to 
cuprous  oxide.  It  also  reduces  certain  mercury  solutions  to  metallic  mercury. 


Laevulose  or  Fructose,  CeH^Oe  (I.) 


This  substance  exists  in  honey.  It  also  exists  widespread  in 
the  vegetable  kingdom  in  fruits,  sometimes  with  glucose,  some- 
times with  cane  sugar. 

It  is  soluble  in  water;  crystallizes;  reduces  Fehling’s  solution;  it  ferments 
with  yeast. 


I IO 


CARBON  COMPOUNDS. 


Maltose,  C12H22O11  (d.) 

This  substance  is  formed  by  the  action  of  malt  on  starch,  an 
operation  due  to  the  existence  in  the  malt  of  a peculiar  unorgan- 
ized ferment  called  diastase. 

Maltose  is  soluble  in  water;  it  crystallizes ; it  reduces  Fehling’s  solution;  it 
ferments  with  yeast;  it  combines  with  phenylhydrazine. 


Lactose  (Milk  Sugar),  C12H22Q11  (d.) 

This  substance  is  produced  in  considerable  quantity  in  Switzer- 
land. The  whey  of  milk  is  evaporated  and  the  sugar  is  then 
crystallized  from  it  upon  threads  hung  in  suitable  vessels. 

Milk  sugar  has  attained  a considerable  consumption  as  a mate- 
rial for  use  by  homoeopathic  physicians.  It  is  also  somewhat 
employed  as  an  addition  to  cows’  milk  used  in  the  feeding  of 
human  infants.  (In  this  case,  it  seems  to  favor  digestion  far 
more  than  any  addition  of  cane  sugar.) 

Lactose  is  soluble  in  water;  it  crystallizes ; it  reduces  Fehling’s  solution ; it 
does  not  ferment  with  pure  yeast;  common  yeast  ferments  it  into  alcohol  and 
lactic  acid ; by  boiling  with  dilute  sulphuric  acid,  it  forms  dextrose  and  galac- 
tose. 


Sucrose  (Cane  Sugar)  C12H22O11  (d.) 

Cane  sugar , called  sucrose . Sucrose  is  sweeter  than  the  other 
true  sugars  and  it  crystallizes  better.  It  is  a most  important 
article  of  human  food.  Sucrose,  as  well  as  the  other  carbohy- 
drates, are  looked  upon  as  fat-producers  in  the  animal  economy 
rather  than  as  muscle-producers.  (For  the  production  of  muscle, 
nitrogenous  food  is  necessary.) 

Cane  sugar,  in  a state  of  absolute  whiteness  and  crystalline 
purity,  as  now  used  so  largely  by  civilized  beings,  is  a compara- 
tively modern  article  of  food.  The  sugar  cane  originated  in  the 
far  East.  In  1495,  it  was  introduced  into  St.  Domingo,  and  a few 
years  later,  into  other  parts  of  the  West  Indies.  The  introduction 
of  sugar  into  Europe  is  usually  considered  to  have  been  one  of 
the  results  of  the  Crusades.  It  was  originally  esteemed  a val- 
uable medicinal  remedy,  and  a little  later  a supreme  luxury  for 
the  rich. 


CARBOHYDRATES ; SUGARS. 


Ill 


Sucrose  is  soluble  in  water,  but  only  sparingly  soluble  in  alcohol;  it  crystal- 
lizes; it  melts  without  decomposition,  but  on  further  heating  it  changes  to  a 
brown  substance  called  caramel;  by  influence  of  a small  amount  of  warm  dilute 
mineral  acid  it  decomposes  into  dextrose  and  laevulose : 

C12H22O11  + H2O  = C6H12O6  4"  C6H12O6 

The  process  is  described  as  inversion  and  the  product  is  spoken  of  as  invert 
sugar ; sucrose  does  not  reduce  Fehling’s  solution;  while  it  may  be  fermented 
by  yeast,  it  does  not  do  so  readily  or  directly. 

The  following  constitutional  formula  for  cane  sugar  has  been 
suggested  : 


H 

hc— OH 
HC 


O 

HC 


The  chief  commercial  sources  of  sucrose  are  the  sugar  cane 
and  the  sugar  beet . In  the  aggregate,  considerable  quantities 
of  sugar  are  manufactured  from  the  sorghum  plant , from  the 
sap  of  the  maple , also  from  the  sugar  palm  (which  sends  into 
commerce  a crude  sugar  called  jaggery ).  In  the  manufacture  of 
crystallized  cane  sugar  from  any  of  these  sources,  the  operations 
may  be  grouped  in  four  stages  : first,  securing  the  vegetable 
juice  ; second,  preliminary*evaporation  ; third,  decolorizing  the 


1 1 2 


CARBON  COMPOUNDS . 


syrups  ; fourth,  crystallizing  the  sucrose.  The  details  of  these 
operations  vary  considerably  according  to  which  of  the  four 
sources  of  supply  is  considered.  Moreover,  in  preparing  sucrose 
from  one  of  these  sources,  different  establishments  employ 
slightly  different  methods. 

First y sucrose  from  the  sugar  cane . After  the  cane  has  been 
cut,  it  is  subjected  to  pressure  by  means  of  large  rollers. 
Squeezed  between  these  rollers,  the  sugary  juice  is  expelled  as  a 
kind  of  syrup.  This  syrup  contains  in  addition  to  sucrose  certain 
other  substances,  particularly  albuminous  substances  which 
afford  conditions  easily  leading  to  such  a fermentation  of  the 
juice  as  will  produce  difficultly  crystallizable  sugars.  The  juice  is 
at  once  raised  in  temperature  and  a portion  of  milk  of  lime  is 
added  in  order  to  precipitate  the  albuminous  matters  and  offer 
resistance  to  this  tendency  to  fermentation.  The  juice  is  further 
heated  to  bring  to  the  surface  flaky  matters,  which  are  skimmed 
off.  In  many  Cuban  plantations,  vacuum  pans  are  employed ; in 
these  the  juice  is  evaporated  nearly  to  the  crystallizing  point. 
Thus  a crude  sugar  is  produced.  This  crude  sugar  is  exported 
to  the  great  commercial  countries  of  the  world  : England,  France, 
Germany,  the  United  States,  where  the  sugar  is  refined. 


In  tropical  countries  the  extraction  of  the  sugar  from  the  cane  is  carried  on 
under  considerable  difficulties.  Hot  climates  are  unfavorable  to  that  untiring 
industry  which  characterizes  the  inhabitants  of  the  great  industrial  countries  of 
Europe  and  the  United  States.  Again,  high  temperature  is  very  injuri- 
ous to  the  juice  when  extracted  from  the  cane:  even  within  an  hour  from  its 
extraction,  fermentation  may  set  in,  such  as  will  generate  uncrystallizable  forms 
of  sugar,  or  even  acetic  acid,  at  the  cost  of  enormous  loss  of  true  sucrose. 
Again,  it  is  found  that  no  amount  of  mechanical  crushing  will  extract  from  the 
cane  its  full  proportion  of  sweet  juice.  Its  silicious  and  woody  exterior  resists 
the  most  powerful  rollers  used  for  this  purpose.  Many  methods  have  been 
attempted  with  a viewr  of  replacing  crushers  ; without  much  success,  however. 
But  the  obstacles  have  been  to  a considerable  extent  conquered  by  the  intelli- 
gent planter  by  the  application  of  energy,  capital,  and  scientific  knowledge. 

In  refining  sugar,  there  are  several  distinct  stages  : i. — The 
crude  sugar  is  dissolved  in  water.  2. — The  syrup  is  carried 
to  the  top  floor  of  the  refinery,  which  is  usually  a very  high 
building.  (In  subsequent  stages,  the  sugar  descends  easily 
from  floor  to  floor.)  The  syrup,  being  carried  into  tanks,  is 
mixed  with  ox-blood  (or  even  sawdust.)  The  albumen  of  the 


CARBOHYDRATES ; SUGARS. 


1 13 


blood  is  capable  of  coagulation  by  heat ; at  the  same  time,  it  is 
very  adhesive.  The  mixture  of  syrup  and  blood  being  heated, 
and  at  the  same  time  agitated,  the  albumen  attaches  to  itself 
particles  of  dirt,  fibre,  mechanical  impurities,  and  to  some  extent, 
coloring  matters.  As  the  coagulation  proceeds,  the  albumen 
forms  hard  lumps  which  may  be  easily  removed  by  the  next 
process.  (The  coagulated  albumen,  known  as  blood-waste,  is 
afterwards  sold  for  use  in  the  manufacture  of  commercial  fer- 
tilizers. It  affords  valuable  nitrogenous  material.) 

3.  — From  the  tanks  just  mentioned,  the  turbid  liquid  is  strained 
through  cloth  bags.  A clear  syrup  passes  through,  leaving  all 
solid  matters  on  the  filters.  The  clear  syrup,  however,  is  some- 
what colored. 

4.  — The  syrup  afforded  by  the  preceding  operation  is  next  carried 
through  filters  of  bone  coal.  (Bone  coal  is  manufactured  by 
heating  bones  in  closed  iron  retorts.  The  mineral  part  of  the 
bone  is  not  altered  by  the  operation,  but  the  gelatinous  matters  — 
the  organic  substances  diffused  through  the  bone  — are  decom- 
posed, and  they  afford  a very  porous  carbon  which  is  very  effect- 
ive in  decolorizing  liquids.)  On  passing  through  the  bone  coal, 
the  syrup  is  completely  decolorized. 

5.  — The  colorless  syrup  from  the  preceding  operation  is  now 
passed  into  the  vacuum  pans.  These  are  immense  boilers,  so  con- 
structed that  evaporation  may  proceed  with  great  rapidity  and  at 
comparatively  low  temperatures.  Their  effectiveness  depends 
upon  the  fact  that  the  upper  portions  of  the  pan  are  continually 
exhausted  of  air  and  water  vapor  by  the  action  of  powerful  pumps. 
Thus  conditions  are  afforded  whereby  water  may  be  vaporized  from 
the  syrups  without  that  restraint  which  would  be  exerted  upon  it  if 
air  or  water  vapor  were  resting  upon  it.  The  vacuum  pans  are 
ingenious  appliances  devised  and  constructed  with  the  highest 
degree  of  scientific  skill.  By  their  means,  the  syrup  is  evaporated 
to  the  condition  of  a saturated  solution  of  sucrose ; and  this  is 
accomplished  without  danger  of  injury  to  the  sucrose  by  excessive 
heat. 

6.  — From  the  vacuum  pans,  the  concentrated  syrup  is  drawn 
out  into  crystallizing  tanks  of  various  kinds.  They  differ  according 
as  the  crystals  desired  are  large  or  small,  moist  or  dry,  separate 


8 


CARBON  COMPOUNDS. 


1 14 


or  coherent.  Sometimes  crystalline  loaves  are  produced,  and 
these  by  the  action  of  saws  are  cut  up  into  small  cubes.  The 
sawdust  in  this  case  is  cane  sugar.  It  is  pulverized  by  machinery 
and  thus  brought  to  the  condition  of  powdered  sugar. 

In  all  these  operations  where  cane  sugar  is  handled,  the  greatest  care  must 
be  taken  to  avoid  fermentation  of  sucrose  into  uncry stalliz able  varieties  of 
sugar.  In  order  to  accomplish  this  result,  the  business  is  conducted  on  a very 
large  scale  and  in  such  a way  that  a given  portion  of  sugar  is  not  long  in  the 
process ; that  is,  a thousand  barrels  of  raw  sugar  received  to-day  are  turned  out 
in  the  form  of  refined  white  sugar  to-morrow. 

Again,  iron  must  be  carefully  avoided;  a small  amount  of  it,  such  as  would 
not  ordinarily  be  recognized  in  sugar,  would  be  detected  when  sugar  is  used  in 
the  sweetening  of  tea.  (Tea  contains  tannin  which  at  once  produces  a dark 
colored  compound  with  iron  ; the  same  principle  being  employed  in  the  manu- 
facture of  writing  inks.)  In  order  to  secure  immunity  from  iron,  wooden 
shovels  are  employed,  and  brass  and  copper  vessels  of  various  sorts.  Wherever 
iron  apparatus  is  necessarily  involved,  it  is  kept  carefully  cleaned  or  protected 
by  paint. 

Cane  sugar , from  the  sugar  beet.  The  manufacture  of  refined 
cane  sugar  from  the  sugar  beet  has  attained  enormous  propor- 
tions in  Europe,  especially  in  Germany,  France,  Russia,  and 
Austria.  It  has  been  attempted  on  a moderate  scale  in  the 
United  States. 

The  German  chemist  Marggraf  observed  in  1747  that  beets 
contain  a sugar  similar  to  that  of  the  sugar  cane  and  that  it  is 
capable  of  crystallization.  His  pupil  Achard  advanced  the  practi- 
cal side  of  the  subject  by  setting  up  an  experimental  works  in 
1769.  Gradually  other  works  were  established  in  Germany.  In 
France,  Delessert  undertook  the  manufacture  of  beet  sugar;  in 
1812,  his  operations  were  brought  to  the  attention  of  Napoleon. 
The  emperor,  who  was  very  anxious  to  encourage  domestic  indus- 
tries in  France,  as  opposed  to  the  purchase  of  goods  from  foreign 
nations,  ordered  the  cultivation  of  an  immense  tract  of  country, 
and  appropriated  a million  francs  to  further  the  undertaking.  A 
large  number  of  chemists  and  manufacturers  studied  the  subject 
thoroughly,  and  ultimately  the  art  of  making  sugar  from  beets 
became  successful. 

It  is  worth  noting  that  the  eminent  German  chemist  Liebig  considered  the 
manufacture  of  beet  sugar  an  unwise  one  for  Germany  on  the  ground  that  cane 
sugar  could  be  produced  cheaper  in  tropical  climates,  whereas  the  beet  sugar  of 
Germany  depended  on  the  taxation  of  a vast  body  of  non-producers  in  order  to 


CARBOHYDRATES ; SUGARS. 


115 


afford  it  the  necessary  government  support.  “ The  satisfaction  of  eating  sugar 
grown  on  our  own  soil,”  he  says,  “is  therefore  purchased  by  a not  inconsider- 
able sacrifice.”  He  refers  to  the  fact  that  the  government  was  paying  manufac- 
turers a bonus  on  beet  sugar  produced;  a state  of  things,  we  may  add,  which 
up  to  the  present  day,  continued  in  one  form  or  another,  has  given  rise  to  grave 
questions  in  Germany.  Apparently,  to-day,  the  tax-paying  citizens  in  Germany, 
the  non-manufacturers  of  sugar,  are  paying  the  German  sugar  manufacturers  a 
certain  contribution  in  order  to  enable  them  to  furnish  beet  sugar  to  the  people 
of  England  and  France  at  cost.  However,  the  assistance  afforded  by  the 
Emperor  Napoleon  and  by  the  German  government  has  developed  the  beet 
sugar  industry  enormously  and  has  brought  it  to  the  condition  of  a very  perfect 
though  very  complicated  manufacture,  and,  more,  inventions  and  discoveries 
put  in  operation  in  the  complex  beet  sugar  industry  have  been  borrowed  to 
great  advantage  in  the  simpler  operation  of  producing  sugar  from  the  sugar 
■cane. 

The  following  is  an  outline  of  the  process  of  manufacture  of 
cane  sugar  from  beets  : 

(1)  Great  care  is  exercised  in  selecting  for  cultivation  beets 
of  a variety  likely  to  produce  the  highest  yield  of  sugar ; in  culti- 
vating these  in  the  most  scientific  manner  so  as  to  develop  in 
them  the  largest  amount  of  sugar  of  which  they  are  capable ; in 
harvesting  them  at  the  period  when  the  sugar  contents  are  at  the 
highest  point. 

(2)  When  harvested,  the  beets  are  washed  to  remove  extra- 
neous impurities.  They  are  sliced  or  rasped  and  treated  with 
water  to  extract  the  sugar.  In  some  cases,  Graham’s  discovery 
of  the  high  diffusion  rate  of  crystalloids  is  employed,  the  juice 
being  placed  in  diffusion  batteries  so  that  the  largest  amount  of 
cane  sugar  may  be  absorbed  in  the  smallest  amount  of  water  and 
with  the  smallest  simultaneous  absorption  of  other  vegetable 
matters. 

(3)  The  juice  is  partly  purified  by  heating  to  coagulate  vege- 
table albumen  and  by  the  addition  of  lime  which  assists  in  this 
operation.  The  liquid  is  then  filtered. 

(4)  The  partly  purified  filtrate  is  next  treated  with  a large 
amount  of  lime  — about  five  per  cent.  This  combines  with  the 
sugar,  forming  an  insoluble  precipitate,  a sort  of  sucrate. 
Another  filtration  separates  this  sucrate  from  liquid  impurities. 

(5)  The  sucrate  of  lime  is  freed  from  lime  by  another  opera- 
tion in  which  carbon  dioxide  (generated  by  heating  limestone  or 
by  burning  coke)  precipitates  the  calcium  as  calcium  carbonate, 
CaC03,  while  the  sugar  is  left  in  solution. 


ii  6 


CARBON  COMPOUNDS. 


(6)  The  syrup  is  now  subjected  to  a series  of  processes  very 
similar  to  those  described  under  the  refining  of  sugar  from  cane, 
such  as  decolorizing  the  syrups  with  bone-coal  and  subsequently 
crystallizing  the  sugar  by  the  use  of  the  most  perfect  mechanical 
appliances,  such  as  vacuum  pans,  etc.  Scientific  study  of  a high 
order  has  been  expended  without  stint,  in  order  to  raise  every 
step  to  a position  of  the  greatest  chemical  economy  and  to 
advance  every  mechanical  appliance  to  a condition  of  the  first 
efficiency. 

Cane  sugar  from  sorghum.  The  sorghum  plant,  or  Chinese 
sugar  cane,  offers  some  advantage  in  the  manufacture  of  sugar, 
in  the  fact  that  it  flourishes  in  comparatively  cool  climates.  Tre- 
mendous efforts  have  been  exerted  to  introduce  the  manufacture  of 
sorghum  sugar  into  the  United  States.  Both  private  individuals 
and  the  Department  of  Agriculture  have  devoted  large  sums  of 
money  and  careful  study  to  the  development  of  this  industry,  In 
some  parts  of  the  United  States,  stimulated  by  State  and  National 
bounties,  sorghum  plantations  and  sorghum  sugar  factories  are 
now  in  operation. 

It  seems  evident  that  small  farmers  cannot  undertake  the  complete  business. 
The  sorghum  must  be  grown  in  a certain  favorable  belt  of  country.  It  must 
be  harvested  under  careful  chemical  supervision  at  exactly  that  time  in  the  year 
when  its  juice  has  attained  its  maximum  contents  of  crystallizable  sugar  with 
the  minimum  of  those  uncrystallizable  ones  which  are  a considerable  drawback 
in  this  industry.  The  sugar  must  be  extracted  from  the  stalk  with  the  most 
carefully  adjusted  diffusion  batteries.  Subsequently,  of  course,  the  juice  must 
be  defecated  and  crystallized  by  the  use  of  those  complex  and  elaborate  com- 
binations of  apparatus  of  which  the  industries  dependent  upon  the  sugar  beet 
and  the  sugar  cane  have  developed  the  use. 

In  brief,  the  process  of  the  manufacture  of  sugar  from  sorghum 
is  as  follows  : 

The  cane  is  first  cut  into  small  pieces,  about  an  inch  in 
length.  Next,  these  pieces  are  subjected  to  the  action  of  a fan, 
whereby  the  light  and  comparatively  worthless  particles  are  blown 
away.  The  better  portions  of  the  cane  are  then  acted  upon  by  a 
shredding  machine  which  tears  the  material  and  gets  smaller 
fragments.  These  fragments  are  submitted  to  the  action  of  the 
diffusion  battery.  In  this  apparatus  the  syrupy  juice  is  extracted. 
This  juice  is  clarified  by  the  use  of  lime,  after  which  it  is  allowed 
to  settle.  Next,  the  clear  juice  is  partially  evaporated  into  a 


CARBOHYDRATES ; SUGARS. 


II 7 


tolerably  thick  syrup.  To  this  syrup,  90  per  cent,  alcohol  is 
added.  By  the  influence  of  the  alcohol,  while  the  real  sugar  is 
dissolved,  certain  impurities  are  thrown  out  in  the  form  of  a sedi- 
ment. The  alcoholic  syrup  being  drawn  off  and  distilled,  the 
alcohol  is  collected  for  a second  use,  while  a purified  syrup 
remains.  This  syrup  is  evaporated  in  vacuum  pans  until  it  is 
sufficiently  condensed  for  the  extraction  of  solid  sugar  from  it. 

The  use  of  alcohol  is,  in  many  ways,  objectionable,  and  sorghum 
sugar  may  be  made  without  it. 

Sugar  from  the  sugar  uiaple.  The  sugar  maple  which  grows 
abundantly  in  the  northeastern  parts  of  the  United  States  affords 
a sugary  juice.  At  the  period  in  early  spring  when  the  sap  is 
known  to  be  richest  in  sugar,  the  mature  trees  are  tapped  ; that 
is,  a small  spout  is  inserted  under  the  bark.  The  juice,  which 
flows  freely,  is  then  quickly  boiled  down  until  it  is  in  a condition 
to  harden.  A yellowish  sugar  and  a clear  and  agreeable  syrup 
may  be  thus  secured.  As  yet,  however,  no  considerable  quanti- 
ties of  highly  refined  white  sugar  are  produced  from  this  source. 

Notes  on  the  Synthesis  of  Sugars. 

This  important  synthesis  usually  starts  with  a-acrose,  a substance  that  may 
be  produced  in  at  least  two  ways  : 

First  way. — In  aqueous  solution,  formaldehyde,  CH20,  by  action  of  milk 
of  lime  polymerises  into  a mixture  of  sugars  called  formose,  CgHi2Og. 

From  formose,  «-acrose,  CgHi2Og,  rnay  be  isolated. 

Second  way. — From  glycerol  (glycerin),  C3H8O3,  by  action  of  sodium  carbon- 
ate and  bromine,  there  is  produced  a kind  of  sugar  called  glycerose  (a  triose) 
CgHeOs. 

From  glycerose,  a-acrose  may  be  produced  by  a spontaneous  polymerisation. 

Next,  starting  with  «-acrose  the  following  briefly  described  sets  of  operations 
lead  to  the  production  of  certain  natural  as  well  as  artificial  sugars  : 


First  Set. 

1.  From  a-acrose,  by  addition  of  phenyl  hydrazine,  there  is  produced  i -gluco- 
sazone. 

2.  From  glucosazone,  by  action  of  concentrated  hydrochloric  acid,  there  is 
produced  i -glucosone. 

3.  From  glucosone,  by  action  of  nascent  hydrogen,  there  is  produced  i-FR.uo 
tose  and  i-mannite  (see  4). 


\ 


CARBON  COMPOUNDS. 


1 1 8 


Second  Set. 

4.  From  i-mannite,  by  oxidation  there  is  produced  i-tnannose. 

5.  From  i-mannose,  by  oxidation  there  is  produced  i-mannonic  acid. 

6.  From  i-mannonic  acid,  by  decomposition  of  the  strychnia  salt  there  is 
produced  1 -mannonic  acid  (see  7)  and  d -mannonic  acid  see  9 and  13). 

Tkird  Set. 

7.  From  1-mannonic  acid,  by  quinoline  there  is  produced  1 -gluconic  acid. 

8.  From  1-gluconic  acid,  by  nascent  hydrogen  there  is  produced  1-glucose* 

Fourth  Set. 

9.  From  d-mannonic  acid,  by  nascent  hydrogen  there  is  produced  d-mannose* 

10.  From  d-mannose,  by  phenyl  hydrazine  there  is  produced  d -glucosazone. 

11.  From  d-glucosazone,  by  hydrochloric  acid  there  is  produced  d-glucosone* 

12.  From  d-glucosone,  by  nascent  hydrogen  there  is  produced  <£-laevulose. 

Fifth  Set. 

13.  From  d-mannonic  acid,  by  heating  with  quinoline,  there  is  produced 
d -gluconic  acid. 

14.  From  d-gluconic  acid,  by  nascent  hydrogen  there  is  produced  d-GLUcosE. 

Note.  Investigators  working  on  the  synthesis  of  sugars,  use  the  symbols 
d,  1,  and  i,  to  express  respectively  series  of  related  compounds  rather  than  dis- 
tinctively optical  properties.  This  produces  a certain  confusion — but  it  is 
unavoidable  for  the  present. 


CHAPTER  XV. 


CARBOHYDRATES  (Continued). 

Starch. 

Distribution.  Starch  is  widely  diffused  in  the  vegetable  king- 
dom. It  is  generally  accumulated  in  seeds  as  the  nutriment  of 
the  young  sprout,  before  the  latter  has  become  sufficiently 
developed  to  draw  food  from  the  soil  and  the  atmosphere. 

It  also  exists  in  roots,  tubers,  and  occasionally  in  bark  and  pith. 
A large  proportion  of  the  edible  potato  is  starch.  The  principal 
kinds  of  starch  employed  as  such  are  wheat  starch,  corn  starch, 
potato  starch,  and  rice  starch. 

Starch  has  not  yet  been  produced  artificially. 

In  preparing  corn  starch  the  corn  is  soaked  in  water  containing  a small 
amount  of  caustic  soda  or  soda  ash.  The  pasty  mass  is  then  placed  on  screens  ; 
the  starch  washes  through ; the  water  and  starch  being  received  in  suitable 
tanks,  are  allowed  to  rest  in  quiet  until  the  starch  has  deposited;  thereupon 
the  larger  portion  of  water  is  drawn  away,  and  the  moist  starch  is  dried  and 
made  ready  for  the  market.  In  drying,  the  mass  of  starch  soon  comes  to  be 
penetrated  by  large  cracks : thus  irregular  lumps  of  starch  are  left.  These 
must  not  be  considered  crystals , for  they  are  not  such  in  any  sense.  On  the 
screens  remain  the  hulls  and  the  germs  of  the  young  corn  plant.  After  drying 
the  mass,  it  is  subjected  to  a process  of  winnowing;  a current  of  air  blows  the 
hulls  into  one  box,  while  the  germs  remain  in  another.  From  the  germs,  corn- 
oil  may  be  produced  by  pressing.  The  pomace  may  be  used  for  feeding  cattle. 

In  preparing  potato  starch,  the  potatoes  are  rasped  into  a pulp.  This  pulp  is 
washed  in  water  so  as  to  float  off  the  starch  and  separate  it  from  coarser  mat- 
ters which  remain  behind.  Subsequently  the  starch  is  allowed  to  subside. 

Properties,  i.  When  examined  under  the  microscope,  the 
starches  of  different  vegetables  present  different  appearances. 
They  are  characterized,  however,  by  one  general  kind  of  forma- 
tion ; that  is,  they  are  formed  in  eccentric  layers,  one  outside  of 
another.  But  starches  from  different  sources  form  granules  dif- 
fering in  size  and  appearance.  The  granules  of  potato  starch  are, 
generally  speaking,  the  largest ; the  granules  of  rice  starch  are, 
generally  speaking,  the  smallest ; while  those  of  other  starches 

(i  19) 


120 


CARBON  COMPOUNDS. 


are  intermediate.  By  the  microscope,  therefore,  different  kinds 
may  be  distinguished  one  from  another,  and  mixtures  of  them 
may  be  detected.  Of  course  for  completeness  of  this  kind  of 
analysis,  reagents  like  iodine  may  sometimes  be  employed  to 
advantage ; and  polarized  light  may  also  be  used. 

2.  To  starch  is  usually  assigned  the  formula  C6H10O5,  what- 
ever the  source  whence  it  is  derived.  Whether  or  not  this  for- 
mula represents  correctly  the  molecule  of  starch,  cannot  be  at 
present  determined.  ' It  is  thought  that  the  formula  (C6H10O5)n  is 
nearer  the  truth.  It  is  not  certain  that  the  same  molecular 
formula  is  appropriate  to  the  different  kinds  of  starch. 

3.  The  various  starches  have  certain  striking  chemical  proper- 
ties in  common.  Thus,  water  solutions  of  iodine  turn  starch  to 
a deep  blue  color.  The  nature  of  the  blue  compound  is  not 
understood.  It  does  not  appear  to  be  a very  stable  one,  since 
starch  blued  with  iodine  loses  its  color  under  the  influence  of 
heating  in  water  and  upon  addition  of  alcohol.  Upon  the  with- 
drawal of  heat  or  the  removal  of  the  alcohol,  the  blue  color  reap- 
pears. 

4.  Starch  by  itself  is  insoluble  in  water  and  all  ordinary  solv- 
ents ; but  a variety  of  starch  called  soluble  starch  may  be  pro- 
duced by  boiling  starch  in  water  for  a considerable  length  of 
time.  The  first  action  of  water  upon  starch,  however,  involves 
merely  an  opening  of  the  layers  in  which  the  granules  are 
formed.  The  portions  constituting  these  layers  being  broken 
off,  and  floating  in  the  water,  give  rise  to  the  tenacious  mass 
known  as  starch  paste. 

5.  Under  the  influence  of  certain  dilute  acids,  aided  by  heat, 
all  kinds  of  starch  change  into  dextrose  or  glucose. 

Under  the  influence  of  strong  nitric  acid,  starch,  like  other  car- 
bohydrates, is  capable  of  forming  nitro-compounds,  as  described 
under  the  head  of  cellulose.  These  compounds  are  derivatives 
in  which  the  nitric  acid  radicle,  N03,  replaces  certain  atoms  of 
the  hydrogen  and,  it  may  be  occasionally,  of  the  oxygen  of  the 
carbohydrate. 

6.  When  starch  is  moderately  baked  it  changes  to  a soluble 
substance  called  British  gum  or  dextrin.  It  is  a mixture  of  car- 
bohydrates of  undetermined  composition. 


CARB OH  YDRA  TES ; STAR CH. 


121 


7.  Malt  extract  (by  virtue  of  its  diastase)  changes  starch  to 
dextrin  and  maltose. 

Uses.  1.  In  the  development  of  the  growing  plant,  a con- 
siderable amount  of  its  energy  is  devoted  to  the  preparation  of 
the  seed.  Here  starch,  as  well  as  other  substances,  are  stored  up. 
In  the  process  of  germination  the  starch  undergoes  a fermenta- 
tion or  modification  into  dextrose,  a soluble  carbohydrate,  which 
affords  nutriment  for  the  young  plant.  When  this  parent  supply 
is  exhausted,  the  more  mature  plant  absorbs  food  from  the  soil 
and  atmosphere  and  then  develops  a new  stock  of  starch  for  its 
successors. 

2.  Starch  is  a prominent  factor  in  the  vegetable  foods  con- 
sumed by  man  and  many  of  the  lower  animals.  In  wheat  flour, 
in  corn  meal,  in  oat  meal,  and  in  many  other  important  kinds  of 
vegetable  food,  starch  is  an  important  constituent. 

When  starch  acts  as  a food  for  man  and  the  higher  animals,  it 
undergoes  certain  changes.  In  the  operations  of  cooking,  the 
starch  is  changed  by  heat  and  fermentation  into  dextrose  or 
glucose,  carbohydrates  more  soluble  and  digestible  than  starch. 
These,  acted  upon  by  the  juices  of  the  digestive  tract,  are 
absorbed  into  the  animal  system  and  contribute  to  the  building 
up  of  certain  of  its  materials.  Farinaceous  matters  contribute  to 
the  production  of  fat  as  distinguished  from  muscle,  which  latter 
demands  nitrogenous  food. 

3.  Starch  is  largely  consumed  in  the  process  of  brewing  malt 
liquors.  The  starch  is  fermented  into  alcohols  (p.  70). 

4.  Starch  is  used  in  making  the  gummy  material  sometimes 
called  British  gum,  sometimes  dextrin,  which  is  used  as  adhesive 
material  on  envelopes  and  postage  stamps ; it  is  also  used  as  a 
thickening  material  for  mordants  used  in  calico-printing.  In 
preparing  dextrin  a small  amount  of  dilute  acid  is  added  to  starch  ; 
then  the  mixture  is  moderately  baked  in  an  oven. 

5.  Starch  is  used  to  produce  glucose  (p.  109). 

6.  Starch  is  used  in  starching  cotton  and  linen  clothing,  and 
in  a similar  operation  called  finishing  of  cotton  and  linen  goods  at 
mills.  It  is  also  used  in  sizing  the  yarn  for  warps  used  in 
weaving. 


v/ 


CHAPTER  XVI. 


CARBOHYDRATES  (Continued). 

Cellulose. 

Distribution.  Cellulose,  C6H10O5,  is  the  principal  constituent 
of  wood.  It  is  also  found  in  very  many  other  portions  of  the 
structure  of  plants.  In  the  leaves  and  flowers,  in  the  harder  and 
less  soluble  parts  of  seeds,  in  the  peculiar  down  which  constitutes 
the  cotton  fibre,  cellulose  exists. 

Cotton  cloth  that  has  been  thoroughly  bleached,  has  gone 
through  a process  which  removes  resins  and  waxes  from  the  sur- 
face of  the  fibre,  and  leaves  a substance  which  is  approximately 
pure  cellulose.  So  old  linen  that  has  been  washed  many  times, 
has  been  thus  freed  from  many  incidental  vegetable  compounds, 
and  it  has  been  reduced  to  a form  of  practically  pure  cellulose. 
In  the  manufacture  of  wood  paper,  the  wood  is  macerated  in  large 
digesters,  whereby  gums  and  resins  are  partly  or  wholly  dissolved. 
There  is  then  left  the  cellular  tissue  of  the  wood  in  fibrous  form. 
(This  way  of  making  the  wood  paper  pulp  must  be  distinguished 
from  another  method  which  is  employed  to  produce  paper  stock. 
In  this  second  method,  the  logs  of  wood  are  forced  against  grind- 
stones, whereby  the  structure  of  the  wood  is  broken  up  and  what 
is  called  ground  wood  is  produced.) 

The  form  of  cotton  used  by  surgeons  and  called  absorbent  cot- 
ton, represents  a nearly  pure  form  of  cellulose.  This  cotton  has 
been  subjected  to  certain  reagents  for  the  express  purpose  of 
removing  the  resin  from  its  surface.  It  absorbs  liquids  with 
much  greater  readiness  than  ordinary  cotton. 

Properties.  i.  Cellulose,  although  a carbohydrate,  and  in 
molecular  formula  supposed  to  correspond  with  starch,  is  in  many 
respects  very  different  from  the  latter.  It  is  but  little  affected  by 
water  and  many  chemicals.  It  is,  however,  dissolved  by  a special 
solution  called  Schweitzer’s  reagent.  This  is  an  ammonical  solu- 

(122) 


CARBOHYDRATES;  CELLULOSE . 


123 


tion  of  cupric  oxide.  It  may  be  prepared  as  follows : Dis- 
solve cupric  sulphate  in  water.  Then  add  ammonium  chloride. 
Next,  add  sodium  hydroxide.  Pour  away  the  clear  liquid,  and 
then  add  the  precipitate  to  ammonium  hydroxide  solution.  A 
deep  blue  solution  is  produced.  This  solution  has  the  remarkable 
property  of  dissolving  cellulose. 

2.  Cellulose  in  the  form  of  wood,  as  portions  of  trees  or  por- 
tions of  buildings,  when  exposed  to  the  air  and  moisture,  under- 
goes a peculiar  decomposition  known  as  rotting  or  decay. 

3.  Hydrocellulose,  C12H220ii,  is  formed  by  the  action  of  cer- 
tain acids  upon  cellulose.  Thus,  strong  sulphuric  acid  or  hydro- 
chloric acid  accomplishes  this  change. 

Cellulose  is  acted  upon  more  by  acids  than  by  alkalies.  Thus, 
concentrated  nitric  acid  turns  it  into  a nitrate  of  cellulose  called 
gun-cotton.  Chlorine,  and  the  gases  evolved  by  bleaching  pow- 
der, have  a corrosive  effect  upon  cellulose.  Bleached  cloth, 
unless  thoroughly  washed  from  the  chlorine  used  upon  it,  often 
becomes  “ tender,”  as  the  bleachers  express  it.  A small  amount 
of  dilute  sulphuric  acid,  placed  upon  cloth,  loses  some  of  its  water 
by  evaporation.  Thereupon,  the  stronger  acid  attacks  the  cloth 
and  rots  it. 

This  general  principle  is  utilized  in  the  woolen  industry.  Certain  kinds  of 
wool,  as  coming  from  the  sheep,  contain  quantities  of  vegetable  seed  vessels 
called  burs.  These  burs  are  not  easily  removed  by  the  carding  operations.  If, 
however,  the  burry  wool  is  treated  with  dilute  sulphuric  acid  and  partially  dried, 
the  acid  attacks  the  cellulose  of  the  burs  without  injuring  the  animal  fibre  of 
the  wool.  If  the  acid  is  then  washed  away  and  the  wool  afterwards  subjected  to 
the  operation  of  carding,  the  burs  are  found  to  be  so  much  affected  by  the  sul- 
phuric acid  that  they  easily  break  up  into  dust  and  separate  from  the  wool. 

A similar  process  is  employed  in  separating  considerable  quantities  of  cotton 
from  wool  in  old  cloths  or  shoddy  which  are  to  be  worked  over.  Sulphuric  acid 
weakens  the  cotton  fibre,  so  that  the  subsequent  manufacturing  operations  may 
save  the  wool  but  let  the  decomposed  cotton  pass  out  as  dust  or  waste. 

So  in  the  so-called  recovery  of  india-rubber,  from  old  rubber  boots  and  shoes, 
the  material  is  heated  with  dilute  sulphuric  acid  which  removes  the  textile  fab- 
ric from  the  gum. 

Parchment  paper.  When  paper  is  allowed  to  rest  for  a short  time  in  concen- 
trated sulphuric  acid  and  is  then  thoroughly  washed  .with  water,  it  is  found  to 
have  undergone  a very  marked  change.  It  shrinks  somewhat  and  becomes 
much  tougher  than  before.  The  substance  produced  is  called  parchment  paper, 
and  it  is  largely  used  as  a covering  material  for  the  corks  of  bottles,  in  substitu- 
tion for  certain  animal  membranes. 


124 


CARBON  COMPOUNDS . 


Nitrates  of  cellulose  ,*  pyroxyline  ; gun-cotton.  When  clean  cotton  is  immersed 
in  nitric  acid,  or  better,  in  a mixture  of  nitric  acid  and  sulphuric  acid,  it 
changes  into  a nitrate.  The  sulphuric  acid  is  used  chiefly  to  withdraw  water 
from  the  nitric  acid  and  so  to  strengthen  it.  The  chemical  action  involves  the 
union  of  the  nitric  acid  radicle,  NO3,  with  the  cellulose,  thereby  replacing  a cer- 
tain number  of  atoms  of  hydrogen  of  the  cellulose.  Several  nitrates  of  cellulose 
are  known,  the  more  explosive  ones  containing  more  of  the  nitric  acid  radicle. 

Thus  a di-nitrate  is  known. 

The  tri-nitrate  and  the  tetra-nitrate  are  often  formed  as  a mixture  by  the 
same  process.  When  these  are  subjected  to  the  action  of  a mixture  of  ethyl 
alcohol  and  ethyl  ether  they  dissolve  and  produce  the  substance  called  collodion. 
If  this  solution  is  exposed  to  the  air  the  solvents  evaporate  and  the  gun-cotton 
is  left  in  the  form  of  a gelatine-like  film.  This  film  has  been  much  employed 
as  a coating  for  glass  negatives  in  photography.  It  has  also  been  used  in  cer- 
tain forms  of  surgical  practice  for  producing  an  artificial  cuticle  upon  wounded 
surfaces. 

K penta-nitrccte  has  been  formed.  It  is  less  stable  than  the  others.  When  a 
a mixture  of  tetra-nitrate  and  penta-nitrate  is  mixed  with  alcohol  and  camphor 
and  the  mass  is  then  thoroughly  kneaded  together  the  peculiar  material  called 
celluloid  is  produced.  The  hexa-nitrate  is  avoided  because  it  is  explosive, 
Celluloid  burns  very  quickly  but  is  not  explosive. 

To  cellulose  hexa-nitrate  the  formula  Ci2H14(N03)6Oio  is  assigned,  will  be 
at  once  seen  to  represent  two  molecules  of  cellulose,  C6H10O5,  in  which  six 
atoms  of  hydrogen  have  been  replaced  by  six  molecules  of  the  nitric  acid  radicle, 
NO3.  After  the  failure  of  many  early  attempts  to  utilize  gun-cotton  as  an 
explosive,  success  has  at  length  been  attained.  At  present,  most  of  the  great 
nations  of  the  world  manufacture  this  material  for  use  in  torpedoes.  It  is 
usually  stored  in  pressed  cakes.  Indeed,  the  substance  is  now  considered  more 
safe  in  use  than  gunpowder. 

Many  terrible  accidents  occurred  before  the  nature  of  gun-cotton  was  well 
understood.  Most  extensive  study  of  it,  however,  has  shown  that  such  acci- 
dents usually  arise  from  gun-cotton  which  has  not  been  washed  perfectly  from 
the  acid  used  in  its  manufacture. 

4.  Cellulose  is  capable  of  undergoing  a kind  of  limited  oxida- 
tion by  action  of  bleaching  powder  solution  with  access  of  air , 
whereby  a brittle  compound  called  a-oxycellulose  is  produced. 
Again,  by  action  of  moderately  strong  nitric  acid  a variety  called 
b-oxycellulose  is  produced. 

5.  Cellulose  not  a food.  The  fact  that  living  plants,  in  their 
processes  of  growth,  produce  much  larger  quantities  of  the  carbo- 
hydrate known  as  cellulose  than  of  the  kindred  carbohydrate 
known  as  starch  is  worthy  of  careful  consideration.  Of  course, 
cellulose  is  cheaper  than  starch,  pound  for  pound.  Cellulose,  how- 
ever, is  not  digestible  in  the  animal  economy  as  starch  is.  In 
other  words,  it  is  not  a true  food.  If  chemists  could  cheaply  turn 


CARB  OH  YDRA  TES  ; CELL  UL  OSE. 


125 


cellulose  into  starch  or  into  glucose,  or  into  sucrose,  the  food  sup- 
ply of  the  world  would  be  materially  enlarged.  (A  somewhat  simi- 
lar transformation  has  been  successfully  accomplished  in  the  change 
of  cellulose  and  starch  into  glucose.  But  while  the  changing  of 
starch  is  cheap  enough  to  be  practicable,  in  case  of  cellulose  it  is 
not  so,  at  present.) 

Uses.  Modern  civilized  nations  use  enormous  quantities  of 
cellulose  in  the  manufacture  of  paper  and  all  the  various  sub- 
stances produced  from  it  ; for  example,  pasteboard,  papier-mache, 
etc.,  and  in  the  manufacture  of  cotton  and  linen  goods. 

Paper, 

While  ancient  peoples  of  the  far  East,  as  the  Egyptians 
and  the  Chinese,  have  long  produced  considerable  quantities 
of  paper  for  a multitude  of  purposes  other  than  for  printed  books, 
for  example,  for  fans,  screens,  wall  decorations,  etc.,  it  has  been 
reserved  for  Western  nations  to  develop  this  industry  to  the 
highest  pitch.  Books  and  newspapers,  paper  boxes,  wall  papers, 
paper  twine,  and  many  other  useful  articles,  suggest  a very  few 
of  the  forms  in  which  paper  or  its  equivalents  are  employed. 

In  the  far  East,  paper  has  been  made  from  many  vegetable 
fibres  which  were  accessible  and  appropriate  for  the  purpose.  In 
Europe,  the  paper  manufacture  originally  employed  discarded 
cotton  or  linen  goods  in  the  form  of  rags.  At  the  present  time, 
while  cotton  and  linen  rags  are  much  used  for  the  finest  qualities 
of  paper,  the  larger  proportions  of  this  useful  material  are  made 
solely  from  wood  or  from  mixtures  containing  large  quantities  of 
wood  pulp. 

The  manufacture  of  paper  from  wood  may  be  briefly  described 
under  two  heads : first,  the  caustic  soda  process  (with  the  soda 
recovery  process)  ; second,  the  sulphite  process. 

The  caustic  soda  process.  First  stage.  Different  kinds  of  wood 
are  used,  but  poplar  is  preferred  ; inferior  kinds  of  wood,  like 
spruce,  may  be  employed.  The  logs  of  wood  are  split  by  a sort 
of  axe,  resembling  an  enormous  chisel,  which  moves  up  and  down 
by  machinery.  When  a log  is  placed  under  the  axe,  the  wood  is 
quickly  split  into  small  pieces.  Next,  the  more  resinous  portions 
of  the  wood  are  removed  by  augers,  which  have  both  a rotating 
motion  and  an  up  and  down  motion,  imparted  to  them  from  the 


126 


CARBON  COMPOUNDS. 


engine.  A log  being  placed  under  the  auger,  a knot  or  dark 
colored  portion  is  quickly  drilled  out  and  the  wood  left  clean. 
Where  “ slabs  ” are  used,  the  bark  or  other  dark  portions,  are 
shaved  off  swiftly  and  economically  by  a series  of  blades  adjusted 
spirally  on  a swift  running  shaft.  The  clean  wood  is  then 
chopped  into  small  fragments,  likewise  by  machine. 

Second  stage.  The  chips  are  boiled  in  large  spherical  kettles, 
called  digesters,  with  a solution  of  caustic  soda  (sodium  hydrox- 
ide). This  liquid  softens  and  dissolves  the  resin,  which  binds  the 
fibres  of  the  wood  together,  so  that  the  material  soon  assumes  the 
form  of  a thick  paste,  or  pulp.  After  boiling  six  or  seven  hours 
under  the  pressure  of  120  pounds,  a large  valve  in  the  digester  is 
opened,  and  the  steam  pressure  drives  the  paste  out  upon  screens. 
Some  of  the  liquid  drains  away  into  a tank  made  to  receive  it ; 
this  liquid  is  afterwards  “ recovered  ” as  described  later.  The 
pulp,  at  first  as  brown  as  black  walnut,  is  thoroughly  washed  with 
water.  Next  it  is  bleached  by  use  of  a small  amount  of  bleach- 
ing powder;  it  becomes  much  lighter  in  color.  By  passing  the 
pulp  through  a screen,  the  water  and  bleaching  powder  are 
removed. 

The  pulp  may  then  be  passed  to  an  ordinary  paper  making 
machine  and  dried  into  the  form  of  a thick  paper.  This  material 
is  often  called  pulp  in  trade  ; it  is  a raw  material,  from  which,  by 
finer  paper-making  machines,  the  better  qualities  of  marketable 
paper  may  be  prepared. 

The  soda  recovery.  The  dark  colored  liquid  that  has  come  away  from  the 
soda  digesters  may  be  described  roughly  as  containing  water,  sodium  hydroxide, 
and  resinous  matters.  The  latter  two  may  be  considered  in  chemical  union,  as 
a sort  of  resinate  of  soda.  In  order  to  recover  the  soda  for  subsequent  use,  the 
liquid  is  subjected  to  several  processes. 

First  process.  The  liquid  is  partly  evaporated  by  some  economical  system  — 
generally  in  vacuum  pans  — the  Yaryan  process  being  a favorable  one.  When 
evaporation  is  sufficiently  advanced,  the  liquid  is  thick  and  brown,  like 
molasses. 

Second  process.  The  thick  liquid  next  flows  into  a peculiar  furnace.  This 
furnace  may  be  described,  in  general,  as  composed  of  three  parts.  There  is  a 
chimney;  at  about  twenty  feet  from  the  chimney  is  a fire-box;  set  diagonally 
between  the  fire-box  and  the  opening  in  the  side  of  the  chimney,  is  a rotating 
iron  furnace,  of  cylindrical  figure,  and  completely  lined  with  fire  brick.  In  the 
fire-box,  chips  and  other  waste  materials  from  slabs,  etc.,  used,  are  burned. 
They  afford  a long  flame,  which  sweeps  toward  the  chimney,  at  the  same  time 


CARBOHYDRA  TES ; CELL UL OSE. 


12  7 


passing  through  the  furnace,  whose  brick  lining  becomes  intensely  heated. 
Now  the  molasses-like  soda  liquid  is  allowed  to  flow  slowly  into  the  upper  end 
of  the  furnace.  It  is  evaporated  ; it  is  heated  red-hot ; its  carbonaceous  matter 
is  partly  oxidized ; so  that  after  taking  a spiral  course,  it  flows  out  of  the  lower 
end  of  the  furnace  as  red-hot  granules.  The  granules  are  received  in  iron 
buckets ; later,  they  are  dissolved,  as  far  as  possible,  in  water.  The  sodium 
carbonate,  formed  in  the  furnace,  dissolves.  A black  carbonaceous  matter, 
somewhat  resembling  graphite,  remains  undissolved. 

Third  process.  The  sodium  carbonate  is  causticised  by  addition  of  quick- 
lime. Calcium  carbonate  is  produced  as  a white  precipitate,  which  is  allowed 
to  settle.  The  clear  liquid  contains  sodium  hydroxide,  i.  e.,  caustic  soda,  which 
is  ready  for  use  in  the  digesters  upon  a new  charge  of  wood. 

The  sulphite  process.  It  has  been  observed  that  bi-sulphites  of 
calcium  and  magnesium  are  very  favorable  materials  for  resolving 
wood  into  pulp.  In  what  is  called  the  sulphite  process,  therefore, 
a bi-sulphite  of  calcium  or  a bi-sulphite  of  magnesium,  must  be 
employed. 

The  apparatus  consists  essentially  of  two  parts.  The  first  part 
is  a series  of  wooden  tanks,  placed  in  the  several  stories  of  the 
building  in  a descending  series.  At  the  bottom  of  the  building  is 
a furnace  for  burning  sulphur.  The  whole  contrivance  is  air-tight, 
except  as  the  manufacturer  opens  valves.  The  general  operation 
of  the  apparatus  permits  a steady  stream  of  liquid,  consisting  of 
water  and  quicklime,  or  water  holding  oxide  of  magnesium  in  sus- 
pension, to  flow  steadily  in  at  the  top  of  the  series  of  tanks  and 
to  be  drawn  steadily  out  at  the  bottom  of  the  series. 

While  the  lime  liquid  flows  downward,  the  sulphur  dioxide  flows 
upward  against  it : that  is,  the  sulphur,  being  burned  on  a hearth 
at  the  lower  part  of  the  building,  forms  sulphur  dioxide  as  a gas, 
which  goes  through  tank  after  tank,  until  it  reaches  the  top  one. 
The  lime  liquid  flows  downward  by  gravity  ; the  sulphur  dioxide 
flows  upward  by  pumping ; that  is,  an  air-pump  connected  with 
the  upper  tank  is  continually  pumping  air  or  gas  through  the 
entire  series.  As  an  ultimate  result,  practically  all  the  sulphur 
dioxide  is  absorbed,  so  as  to  form  bi-sulphite  of  lime.  The  sys- 
tem is  efficient  for  several  reasons.  In  the  first  place,  the  last 
portions  of  the  sulphur  dioxide,  what  may  be  called  the  weakest 
portions,  are  in  the  highest  tank  where  the  lime  is  strongest.  Of 
course  here  absorption  is  most  active.  Again,  the  pumps  have  a 
tendency  to  produce  a rarification  in  the  tanks.  Thus,  the  ten- 
dency is  for  air  to  leak  into  the  system,  rather  than  for  sulphur 


28 


CARBON  COMPOUNDS. 


dioxide  to  leak  out,  where  it  would  be  wasted  and  where  it  would 
cause  annoyance  to  the  workmen  on  the  premises. 

In  the  second  part,  the  bi-sulphite  of  lime,  formed  as  described, 
is  pumped  into  digesters  where  chips  of  wood  are  placed,  and 
digestion  then  proceeds  in  a manner  somewhat  similar  to  that 
already  described  under  the  head  of  the  soda  process. 

The  sulphite  process  is  usually  applied  to  poplar  wood,  so  as  to 
produce  a higher  grade  of  pulp  than  that  afforded  by  the  soda 
process  ; which  latter  is  applied  to  spruce  and  inferior  woods. 
The  sulphite  pulp  is  whiter  than  that  produced  by  the  soda  proc- 
ess, and  is  suitable  for  the  manufacture  of  the  higher  grades  of 
paper. 

Textiles. 

Cotton  has  long  been  known  in  the  far  East.  It  was  woven 
into  cloth  in  the  times  of  the  Pharaohs.  Mummy  cases  recently 
opened  have  been  found  to  contain  cloth  which  upon  examina- 
tion by  the  microscope  was  clearly  shown  to  be  made  from  cot- 
ton. Cotton  is  still  grown  in  large  quantities  in  Egypt  and  India. 
The  United  States  is  the  great  cotton  producing  country  of  the 
world.  The  Sea-Island  cotton  is  of  long  staple  and  of  fine  quality. 

Cotton  as  growing,  is  closely  attached  to  seeds.  The  fibre  is  separated  from 
the  seeds  by  a machine  called  the  cotton  gin.  (Within  a few  years  the  mate- 
rials in  the  seed  have  been  utilized.  The  hulls  are  used  for  fuel ; and  the  ashes, 
rich  in  potassium  salts  and  phosphates,  are  used  as  fertilizers.  The  kernel  is 
pressed  for  oil.  The  cake,  containing  some  oil,  together  with  starch  and  vege- 
table albumenoids,  is  used  as  a food  for  cattle.  The  oil  expressed  is  bleached, 
and  much  used  as  a salad  oil  and  in  the  manufacture  of  soap.) 

When  an  individual  fibre  of  cotton  is  examined  by  the  micro- 
scope, it  presents  the  appearance  of  a tube  that  has  been  flattened 
and  then  twisted  into  a spiral.  Its  tubular  structure  assists  mate- 
rially in  its  retaining  dye-stuffs  applied  to  it,  although  some  colors 
adhere  only  to  the  surface.  Its  spiral  condition  enables  one  fibre 
to  attach  itself  to  another  fibre,  thus  enabling  the  cotton  to  be 
spun  into  fine  thread. 

If  cotton  is  picked  before  it  is  ripe,  its  fibres  are  defective  and 
immature  and  less  able  to  hold  coloring  matters  applied  to  them. 

A considerable  portion  of  the  work  of  cotton  machinery  has  as 
its  aim  the  placing  of  the  individual  fibres  in  parallel  lines. 
Later,  portions  of  these  fibres  are  twisted  so  as  to  produce  what 


CARBOHYDRA  TBS. 


129 


is  technically  called  yarn.  The  length  of  an  individual  fibre  is 
called  its  staple.  Of  course,  the  finer  grades  of  yarn  demand  a 
longer  staple. 

Flax,  jute,  hemp,  and  ramie,  vegetable  fibres  largely  used  for 
the  manufacture  of  textile  products,  may  be  considered  as  forms 
of  cellulose. 


Gums. 

There  exist  in  a great  many  plants  certain  carbohydrates  called 
gums.  They  lack  crystalline  form  ; they  lack  the  granular  struc- 
ture exhibited  by  starch.  They  are  characterized  chiefly  by  the 
chemical  constitution  represented  by  the  formula  (C6H10O5)n  ; and 
by  a tendency,  when  treated  with  water,  to  swell  up  and  form  a 
gelatinous  mass. 

Arabin  is  the  name  applied  to  the  gum  of  gum  arabic.  This  substance  forms 
as  an  exudation  upon  the  bark  of  trees  of  the  acacia  variety.  It  is  obtained 
chiefly  from  the  interior  of  Africa  through  upper  Egypt. 

Gum  arabic  is  employed  in  the  arts  and  in  medicine.  Large  quantities  are 
used  in  the  manufacture  of  mucilage,  in  the  thickening  of  ink,  in  the  prepara- 
tion of  water  colors,  and  for  a few  other  purposes. 

Gelose  exists  in  agar-agar,  or  Ceylon  moss.  It  is  largely  used  as  a thickening 
in  jellies,  soups,  etc.  It  is  also  considerably  employed  as  a medium  for  the 
development  of  microbes  in  bacteriological  experiments. 

Bassorin  is  the  special  material  characterizing  gum  tragacanth.  This  sub- 
stance is  remarkable  for  swelling  enormously  when  placed  in  water.  It  forms 
an  excellent  paste  for  certain  commercial  uses. 

Many  other  plants  afford  certain  varieties  of  mucilage  anala- 
gous  to  gums  and  belonging  to  the  general  class  of  carbohydrates. 
Thus,  from  linseed  oil,  from  quince,  from  Irish  moss,  and  many 
other  substances,  gum-like  products  are  obtained. 


Glucosides. 

The  members  of  the  class  of  bodies  called  glucosides  are  widely 
distributed  in  vegetable  structures  (and  to  some  extent  in  animal 
structures). 

The  primary  feature  of  glucosides  is  this  : by  certain  simple 
operations  they  are  resolved,  by  a kind  of  hydrolysis,  into  two  or 
more  substances,  one  of  which  is  glucose  or  some  other  sugar. 

9 


130 


CARBON  COMPOUNDS. 


Various  agencies  are  capable  of  accomplishing  or  aiding  the 
hydrolysis  : 

1.  Heating  with  water. 

2.  Heating  with  water  and  an  acid  or  an  alkali. 

3.  Action  of  certain  ferments  like  emulsin , erythrozym , 
myrosin , etc.  (Some  glucosides  exist  in  the  plant  associated  with 
certain  nitrogenous  matters  which  latter  may  act  as  an  appropri- 
ate ferment  in  the  particular  case.) 

Glucosides  are  generally  solids;  they  are  generally  rather  neu- 
tral in  reaction  ; they  are  usually  extracted  from  parts  of  plants 
by  solution  in  water  or  dilute  alcohol ; most  of  them  consist  of 
carbon,  hydrogen  and  oxygen  ; some  of  them  contain  nitrogen. 

Following  is  a list  of  a few  important  glucosides  : 

Arbutin,  Ci2H1607,  occurring  in  arbutus, 

Salicin,  C13H18O7,  occurring  in  willow  bark. 

Aesculin,  CisHigOg,  occurring  in  bark  of  horse-chestnut. 

Coniferin,  Ci6H2208,  occurring  in  sap  of  coniferce. 

Ruberythrin,  C26H28O14,  occurring  in  madder  root ; it  yields  alizarin. 

Morindin,  C26H28O14,  occurring  as  a coloring  matter  in  morinda  tinctoria. 

Quercitrin,  C36H38O20>  occurring  in  quercitron  bark. 

Amygdalin,  C20H27NO11,  occurring  in  bitter  almonds. 

Indican,  C26H31NO17,  occurring  in  indigo. 


CHAPTER  XVII. 


FATTY  COMPOUNDS  CONTAINING  NITROGEN  AND 
SIMILAR  NON-METALS. 


Amines,  Amides,  Phosphines,  etc. 

i.  A very  large  proportion  of  the  compounds  already  discussed 
are  capable  of  forming  substitution  compounds  containing  nitro- 
gen. In  some  of  these  the  nitrogen  atom  acts  with  3 points  of 
attraction  ; in  some  with  5. 


For  example  : 


l H 


Ammonia 

gas 


I'  ch3 

N \ H 

I 

l H 


N 1 


r ch3 

1 

ch3 

ch3 


Methylamine  Trimethyla- 
mine 


r h 

' C2H, 

H 

H 

\ H N -j 

H 

H 

H 

. Cl 

_ I 

Ammonium  Ethylammonium 
chloride  iodide 


2.  Some,  but  by  no  means  all,  of  the  nitrogen  compounds  of 
the  class  mentioned,  are  paralleled  by  closely  corresponding  com- 
pounds of  phosphorus,  of  arsenic,  and  of  antimony. 


For  example : 

J'CH, 

P \ H 

l H 

Methylphosphine 


j'  ch3 

As  I CH3 


l ch3 

Trimethylarsine 


f c2h5 
Sb  j c2h5 
L c2h5 

Triethylstibine 


3.  The  nitrogen  compounds  may  be  regarded  from  either  of 
two  points  of  view  ; first , the  alkyl,  or  other  similar  radicles,  may 
be  considered  as  the  passive  or  type  compounds,  and  then  the 
nitrogen  radicle  may  be  considered  as  the  active  replacing  factor  ; 
second , the  nitrogenous  compound  (for  example,  ammonia  gas, 

(13O 


132 


CARBON  COMPOUNDS. 


NH3,)  may  be  considered  as  the  passive  or  type  compound,  and 
then  the  alkyl  radicle,  or  other  carbon  compound,  may  be  con- 
sidered as  the  active  replacing  factor. 

Thus  ethylamine,  C2H5*NH2,  may  be  considered  as  an  ethane,  in  which  one 
atom  of  hydrogen  has  been  replaced  by  the  radicle  amidogen,  NH2;  or  it  may 
be  considered  as  a kind  of  ammonia  gas,  in  which  one  atom  of  hydrogen  has 
been  replaced  by  the  monad  radicle  ethyl,  C2H5. 

Either  view  is  correct;  both  should  be  kept  in  mind;  the  one  or  the  other 
should  be  chiefly  considered,  at  a given  moment,  according  to  convenience. 
The  second  view  is  of  considerable  importance  from  the  fact  that  compounds 
are  known  which  represent  replacement  in  ammonium  compounds  like  ammo- 
nium chloride,  NH4C1,  and  ammonio-platinic  chloride  (NH4)2PtCl6,  for  exam- 
ple, ethylammonio-platinic  chloride,  (NH3C2H5)2P-tCl6. 

4.  In  considering  nitrogen  compounds  of  the  general  group 
under  consideration,  the  student  must  keep  in  mind  the  radicles, 
ammonium,  NH4,  ammonia  gas,  NH3,  hydrazine,  NH2’NH2,  ami- 
dogen, NH2,  imidogen,  NH,  and  finally,  nitrogen,  N. 

Amines.  1.  Very  many  amines  are  known,  but  they  are  more 
important  chemically  than  industrially.  Some  exist  in  natural 
substances  ; many  are  produced  artificially. 

2.  An  amine  is  classed  as  a mono,  di,  tri,  tetra-amine,  accord- 
ing as  its  molecule  is  viewed  to  be  derived  from  one  or  two  or 
three  or  four  molecules  of  ammonia  gas,  respectively. 

3.  The  monamines  are  classed  as  primary,  secondary,  tertiary, 
according  as  one,  two,  or  three  of  the  hydrogen  atoms  of  ammo- 
nia gas,  NH3,  are  replaced  in  the  given  compound  by  the  alkyl 
radicle  or  radicles:  thus  methylamine,  NH2(CH3),  is  a primary 
monamine  ; dimethylamine,  NH(CH3)2,  is  a secondary  monamine  ; 
trimethylamine,  N(CH3)3,  is  a tertiary  monamine. 

4.  The  amines  are  prepared  by  various  methods.  One  is  by 
action  of  an  alkyl  iodide  or  similar  compound  upon  ammonia  in 
alcoholic  solution.  Thus  ethylamine  may  be  prepared  : 

c2h5i  + nh3  = nh3c2h5i. 

Ethyl  Ethylammonium 

iodide  iodide 

Here  the  ethylamine  in  accordance  with  its  similarity  to  ammonia 
gas  and  its  general  basic  character  combines  with  hydriodic  acid  to 
form  the  salt  represented,  ethylammonium  iodide  ; but  from  this 


FATTY  AMINES,  ETC. 


133 


salt  ethylamine  can  be  prepared  subsequently  by  distillation  with 
potassium  hydroxide  (and  subsequent  purification  of  the  distillate). 

5.  The  amines  are  generally  volatile  liquids  of  alkaline  ten- 
dency. They  generally  afford  vapors  that  are  combustible. 

Methylamine,  NH2’CH3,  dimethylamine,  NH(CH3)2,  and  tri- 
methylamine,  N(CH3)3,  exist  in  herring  brine.  They  are  formed 
by  the  decomposition  of  nitrogenous  matters.  These  amines  are 
also  produced  with  other  matters  by  the  dry  distillation  of  certain 
residual  products  formed  in  the  beet  sugar  industry.  Here  also 
nitrogenous  matters  in  the  beet  pulp  afford  the  amines. 

Ethylamine,  NH2'C2H5.  This  substance  is  produced  by  the 
putrefaction  of  certain  substances,  yeast,  for  example.  It  is  also 
formed,  together  with  other  products,  when  the  molasses  of  the 
beet-sugar  manufacture  is  subjected  to  dry  distillation.  It  may 
be  produced  in  the  laboratory  by  a variety  of  methods. 

It  is  a colorless  inflammable  liquid,  possessing  an  ammoniacal 
odor  and  alkaline  reaction.  It  forms  white,  smoky  fumes  with 
hydrochloric  gas  as  ammonia  gas  does. 

Many  other  amines  are  known.  The  amines  produce  also  a 
great  number  of  compounds  by  replacement  with  chlorine  and 
other  halogens,  and  by  combination  with  other  radicles. 

Hydrazines  and  diamines.  Amines  containing  two  atoms  of 
hydrogen  fall  into  one  of  two  groups.  The  hydrazines  are  formed 
from  hydrazine,  NH2'NH2;  in  them  the  two  nitrogen  atoms  are 
linked;  methylhydrazine,  NH2'NHCH3,  is  an  example.  The  dia- 
mines, however,  are  linked  by  the  carbon  atoms  ; ethylenediamine, 
NH2‘CH2,CH2,NH2,  is  an  example. 

Amino  alcohols.  In  the  molecules  of  certain  alcohols  nitrogen 
or  nitrogen  radicles  may  enter.  Thus  from  ethyl  alcohol, 
CH3-CH2OH,  an  aminoethyl  alcohol,  NH2CH2CH2OH,  may  be 
formed. 

Amido  acids  and  acid  amides.  When  a nitrogen  radicle  is 
properly  introduced  by  substitution  into  the  molecule  of  a fatty  acid 
the  replacement  may  occur  in  at  least  two  ways.  Thus  if  amido- 
gen,  NH2,  is  to  be  substituted,  it  may  be  introduced  either  into 
the  alkyl  radicle  of  the  acid,  forming  an  amido  acid , or  into  the 
carboxyl  of  the  acid,  forming  an  acid  amide.  Thus  from  acetic 
acid,  HO’OC'CHg,  there  may  be  formed  amido  acetic  acid, 
HO'OC’CH2NH2,  or  acetamide,  NH2‘OC‘CH3. 


134 


CARBON  COMPOUNDS. 


In  case  of  certain  dibasic  acids  like  carbonic  acid  and  oxalic 
acid,  both  amides  and  amic  acids  may  be  formed.  Thus  : 


HO) 

HO  ) 

NH2) 

^CO 

> CO 

vco 

HO  J 

nh2) 

nh2J 

Carbonic 

Carbamic 

Carbamide 

acid 

acid 

(Urea) 

HOOC 

HOOC 

NH2OC 

HOOC 

NH2OC 

nh2oc 

Oxalic 

Oxamic 

Oxamide 

acid 

acid 

Cyanogen  compounds  and  nitriles.  The  substance  cyanogen, 
CNCN,  and  hydrocyanic  acid,  H’CN,  and  other  cyanogen  com- 
pounds, have  been  referred  to  already  in  another  place.  But  the 
cyanogen  radicle  CN  may  be  looked  upon  as  a derivative  of 
methyl,  CII3,  the  nitrogen  atom  in  cyanogen  replacing  the  three 
hydrogen  atoms  in  methyl.  But  cyanogen,  being  a monad  radicle, 
may  be  considered  as  a unit  capable  of  replacing  other  monad 
radicles,  simple  or  composite.  By  such  replacement  cyanogen 
may  form  at  least  two  sets  of  compounds  : the  first , the  cyanogen 
acids , in  which  cyanogen  replaces  radicles  in  the  alkyl  part  of  an 
organic  acid  ; the  secondy  the  nitriles , in  which  the  cyanogen 
replaces  the  carboxyl  of  an  acid.  Thus  from  acetic  acid, 
HOOC'CH3,  may  be  formed  cyanoacetic  acid,  HOOC‘CH2CN, 
also  a nitrile,  acetonitrile,  NC*CH3.  (Certain  nitriles  are  alkyl 
cyanides  : acetonitrile  is  methyl  cyanide.) 


CHAPTER  XVIII. 


CERTAIN  ORGANIC  COMPOUNDS  CONTAINING 
METALLIC  ELEMENTS. 

A very  large  number  of  the  compounds  already  referred  to  are 
capable  of  forming  molecules  in  which  metals  enter  by  substitu- 
tion. The  most  familiar  and  evident  examples  are  the  acids. 
These  form  metallic  compounds,  of  one  sort  and  another,  in  which 
the  most  common  are  the  salts  resulting  from  the  replacement  of 
the  hydrogen  of  the  carboxyl  by  one  or  more  atoms  of  a metal  or 
metals.  In  most,  if  not  all  of  such  cases,  the  metal  is  indirectly 
attached  to  carbon. 

But  a considerable  number  of  compounds  are  known,  in  which 
the  metal  is  directly  united  to  carbon. 

A few  examples  are  given  : 

Bismuth  trimethide,  Bi(CH3)3 
Sodium  ethide,  NaC2H5 

Glucinum  ethide,  Be(C2Hs)2 
Magnesium  ethide,  Mg(C2Hs)2 
Zinc  propide,  ZnC3H7 

Cadmium  methide,  Cd(CH3)2 

Other  compounds,  of  a similar  type  or  more  complex,  are  known  in  which 
enter  mercury,  aluminium,  thallium,  germanium,  tin,  lead,  and  uranium. 


(I35) 


CHAPTER  XIX. 


AROMATIC  COMPOUNDS. 

General  Statements. 

Probably  chemists  have  devoted  more  study  to  the  aromatic  and 
their  allied  compounds  than  to  any  other  group  of  substances ; 
two  chief  reasons,  the  one  theoretical  and  the  other  practical, 
may  be  assigned.  The  former  is  the  remarkable  theory  of  Kekule 
that  the  molecule  of  benzene,  C6H6,  has  a certain  ring-like  struc- 
ture. The  latter  is  the  fact  that  an  enormous  number  of  colored 
compounds  suitable  for  dyeing,  the  so-called  coal-tar  colors,  may 
be  produced  from  aromatic  hydrocarbons. 

Somewhat  as  the  fatty  compounds  are  viewed  as  derived  from 
marsh  gas,  methane,  CH4,  the  aromatic  compounds  are  viewed  as 
derived  from  benzene,  C6H6,  Aromatic  molecules  contain  the 
benzene  nucleus,  C6,  one  or  more  times,  and  of  course  in  addition 
other  elements. 


While  a ring  formation,  based  on  the  benzene  nucleus,  is  characteristic  of 
aromatic  compounds,  many  other  ring  formations  are  known  : molecules  are 
known  having  as  nuclei  3,  or  4,  or  5 atoms  of  carbon.  Thus  : 


H2 

C 

/ \ 

h2c— ch2 


Trimethylene 


h2c— ch2 

I I 

h2c— ch2 


Tetramethylene 


H2 

c 

/ \ 

h2c  ch2 

\ I 

h2c— ch2 

Pentamethylene 


Other  ring  molecules  are  known  in  which,  while  only  carbon  is  in  the 
nucleus,  a different  linkage  prevails.  Again,  ring  molecules  are  known  in 
which^nitrogen,  or  oxygen,  or  sulphur,  in  one  style  of  linkage  or  another, 
exist  in  the  nucleus.  Moreover  molecules  are  known  in  which  rings  of  various 
sorts  are  conjugated,  that  is,  bound  together. 


036) 


AROMATIC  COMPOUNDS. 


37 


General  Characteristics. 

First.  The  aromatic  compounds  are  proportionally  richer  in 
carbon  than  the  fatty. 

Second.  While  the  fatty  compounds  readily  yield,  by  decompo- 
sition, marsh  gas,  the  aromatic  compounds  by  similar  methods  of 
treatment  generally  yield  benzene. 

Third.  It  is  comparatively  easy  to  turn  one  aromatic  com- 
pound into  another,  or  to  turn  one  fatty  compound  into  another ; 
but  while  possible,  it  is  not  easy  to  turn  a fatty  compound  into  an 
aromatic  compound  or  vice  versa.  When  one  of  these  latter 
kinds  of  change  is  made,  it  involves  a deep-seated  alteration  of 
structure. 

Fourth.  In  the  aromatic  hydrocarbons,  and  their  derivatives,  it 
is  comparatively  easy  to  replace  the  hydrogen  atoms.  Thus  such 
replacement  occurs  in  case  of  radicles  like  chlorine,  hydroxyl, 
amidogen,  methyl,  carboxyl,  the  nitro  group,  the  sulphonic  group. 
The  last  two  are  worthy  of  particular  notice.  Nitric  acid  and 
sulphuric  acid  when  added  to  aromatic  hydrocarbons,  produce 
respectively,  nitro  compounds  and  sulphonic  acids.  The  same 
treatment  applied  to  the  fatty  compounds  produces  a different 
class  of  substances,  the  esters  (in  the  case  of  alcohols) ; or  else  it 
produces  no  change. 

Fifth.  The  aromatic  compounds  have  a peculiar  kind  of  iso- 
merism. They  produce  ortho , meta , and  para , and  other  kinds 
of  isomers  ; forms  of  combinations  not  recognized  in  case  of 
the  fatty  compounds. 

Moreover,  in  certain  aromatic  compounds,  substitution  may 
take  place  either  in  the  benzene  nucleus  or  in  the  side  chain. 

Sixth.  When  hydroxyl  replaces  hydrogen  of  the  nucleus  of 
aromatic  hydrocarbons  there  result  phenols,  substances  very  dif- 
ferent from  the  alcohols  produced  by  fatty  compounds.  The 
phenols  manifest  acid  tendencies,  especially  when  further  substi- 
tutions of  chlorine,  bromine,  iodine,  or  the  nitro  group,  or  the 
sulphonic  group,  occur. 

Seventh.  In  a molecule  of  benzene,  the  simplest  aromatic 
compound,  and  yet  more  in  the  higher  aromatic  hydrocarbons, 
several  radicles  may  at  once  replace  several  hydrogen  atoms,  and 
this  with  comparative  ease. 


38 


CARBON  COMPOUNDS. 


Eighth.  While  members  of  the  fatty  series  tend  to  produce 
colorless  compounds,  members  of  the  aromatic  series  tend  to  pro- 
duce colored  compounds. 


The  Benzene  Ring. 

In  accordance  with  Kekule  s theory  which  is  now  very  widely 
received,  the  constitution  of  benzene  is  ordinarily  represented  as 
a ring  of  six  carbon  atoms,  each  one  attached  to 
its  neighbor  by  one  point  of  attraction  on  the  one 
side  and  by  two  points  of  attraction  on  the  other. 

The  graphic  formula  expressed  in  full  is  that 
given  in  the  margin.  This  method  of  representing 
the  substance  has  been  objected  to  by  some  chem- 
ists, and  two  or  three  other  systems  have  been  devised. 


I 

c 

\ 

-c  c— 
I II 
-c  c— 

% / 
c 


Some  chemists  prefer  Ladenburg’s  method  which 
represents  benzene  as  a triangular  prism,  the  car- 
bon atoms  being  placed  respectively  at  the  six  solid 
angles. 


Von  Baeyer’s  view  is  preferred  by  many.  This  view  is 
approximately  expressed  by  the  adjacent  diagram  for 
benzene  (which  accords  with  facts  as  well  as  the  other 
^ diagrams). 

Von  Baeyer’s  theory  accords  well  with  the  view,  now 
widely  held,  that  the  points  of  attraction  of  a carbon  atom  exist 
in  space  as  if  at  the  apexes  of  a tetrahedron.  If  six  such  tetrahe- 
drons are  allowed  to  stand  compactly  on  a table,  there  appear  six 
summits  at  which  six  hydrogen  atoms  may  be  attached  (C6H6). 


Grounds  for  Acceptance  of  Kekule^s  or  Some  Similar 
Formula  for  Benzene. 

The  structural  formula  devised  by  Kekule  for  benzene  is  now 
generally  adopted.  While  it  is  open  to  certain  theoretical  objec- 
tions, it  has  proved  highly  useful  in  practice.  The  following 
propositions  with  respect  to  the  benzene  molecule  are  discussed 
upon  the  temporary  assumption  that  Kekule’s  formula  is  true  ; 
but  many  of  the  facts  (and  inferences)  apply  with  equal  force 
to  the  other  structural  formulas  proposed : 


AROMATIC  COMPOUNDS. 


139 


First.  The  empirical  formula  of  benzene  is  CeH6.  Quantitative  analysis 
shows  that  the  carbon  and  hydrogen  in  the  molecule  bear  to  each  other  the  rela- 
tions required  by  this  formula. 

The  vapor  density  of  the  substance  leads  to  the  adoption  of  this  formula  as 
against  the  double,  treble,  or  any  other  higher  multiple  of  it. 

Second.  In  the  benzene  molecule  CeHe,  at  least  some  of  the  bonds  of  attrac- 
tion between  the  adjacent  carbon  atoms  are  greater  in  number  than  one ; for 
admitting  that  the  carbon  atoms  in  the  benzene  molecule  assume  the  form  of  a 
ring,  if  all  of  these  carbon  atoms  were  attached  to  neighboring  atoms  by  only 
one  point  of  attraction,  the  hydrocarbon  would  require  the  formula  CgH^. 
(Such  a benzene  derivative  has  indeed  been  practically  realized,  so  has  a some- 
what equivalent  compound,  CgH6C16,  produced  from  benzene.  But  this  may  be 
called  an  addition  compound  as  distinguished  from  a substitution  compound.) 
Now  substitution  compounds  like  CeHsCl,  C6H4Cl2,  C6H3Cl3,  C6H2CI4,  CeHCls, 
and  CeCl6,  have  been  produced. 

Many  other  such  substitution  compounds  are  well  known  : compounds  formed 
on  the  type  of  those  just  enumerated,  only  having  radicles  other  than  Cl  substi- 
tuted for  H. 

Since,  then,  an  atom  of  carbon  is  admitted  (on  the  basis  of  facts  not  here 
stated)  to  have  four  points  of  attraction,  it  is  evident  that  in  the  benzene  ring 
some  of  the  atoms  of  carbon  are  attached  to  other  atoms  by  more  than  one 
point. 

Third.  The  atoms  of  carbon  in  the  benzene  ring  are  of  equal  value  and 
chemical  force. 

When  one  atom  of  chlorine  is  made  to  replace  one  atom  of  hydrogen  by 
proper  chemical  operations,  the  compound  monschlorbenzene,  C6H5CI,  is  pro- 
duced. The  composition  of  this  substance  has  been  learned  by  quantitative 
analysis.  Many  times  and  by  many  different  methods  the  substance  having  the 
formula  stated  has  been  made.  All  these  different  portions  of  this  particular 
compound  or  substance  are  alike.  Up  to  the  present  time,  therefore,  but  one 
hind  of  compound  having  the  composition  C6H5CI,  has  been  produced.  This 
sustains  the  proposition  just  stated,  since  it  may  be  assumed  that  in  different 
times  of  the  manufacture  of  the  substance  in  question,  different  atoms  of  carbon 
in  a given  molecule  of  benzene  have  had  one  atom  of  hydrogen  replaced  by  one 
atom  of  chlorine. 

In  these  cases  if  the  different  atoms  of  carbon  of  the  benzene  molecule  had' 
different  chemical  power  or  relations,  different  isomers  of  the  substance 
named  would  have  been  obtained;  but  no  such  isomers  have  been  obtained. 

The  same  line  of  argument  may  be  employed  with  other  compounds  of  a 
similar  general  nature,  for  example,  compounds  in  which  one  atom  of  bromine, 
one  atom  of  iodine,  one  molecule  of  hydroxyl,  one  molecule  of  the  nitro  group, 
one  molecule  of  the  sulphonic  group,  and  of  others,  have  been  used  to  replace 
one  atom  of  hydrogen  in  a molecule  of  benzene.  In  no  case,  however,  in  suck 
single  replacements  have  isomers  been  obtained. 

These  additional  facts  further  sustain  the  opinion  that  the  carbon  atoms  of 
the  benzene  molecule  have  all  the  same  chemical  quality  and  character. 

These  facts  seem  further  to  prove  that  what  may  be  called  the  extra  points  of 
attraction  of  the  carbon  atoms  are  evenly  distributed  throughout  the  ring. 


140 


CARBON  COMPOUNDS. 


Then  the  proper  distribution  of  the  extra  points  of  attraction  will  be  symmetri- 
cal. 

In  accounting  for  the  formation  of  the  compound  C6H6C16,  it  may  be 
assumed  that  one  point  of  attraction  swings  out  from  each  carbon  atom  to 
attach  an  extra  atom  of  chlorine  to  the  molecule. 

Fourth.  In  the  general  cases  of  compounds,  where  more  than  one  atom  of 
an  element,  or  molecule  of  a radicle,  is  substituted  for  hydrogen,  substances  of 
the  following  types  may  be  considered  : 

(a)  Compounds  of  the  general  formula  C6H4A2. 

(b)  Compounds  of  the  general  formula  C6H3A3. 

(c)  Compounds  of  the  general  formula  CeH3AB2. 

(d)  Compounds  of  the  general  formula  CeH3ABC. 

(a)  Disubstitution  products.  Compounds  of  the  general  formula  C3H4A2. 
Of  these,  in  a given  case,  three  isomers  have  been  recognized. 

(b)  Trisubstitution  products.  Compounds  of  the  general  formula  CeH3A3. 
Of  these,  in  a given  case,  three  isomers  have  been  recognized. 

Compounds  of  the  general  formula  C6H3AB2.  Of  these,  in  a given  case,  six 
isomers  are  possible. 

Compounds  of  the  general  formula  C3H3ABC.  Of  these,  in  a given  case, 
ten  isomers  are  possible. 

(c)  Tetrasubstitution  products.  Compounds  of  the  general  formula  C3H2A4. 
Of  these,  in  a given  case,  three  isomers  have  been  recognized. 

Compounds  of  the  general  formula  CeH2AB3.  Of  these,  in  a given  case, 
seven  isomers  are  possible. 

Compounds  of  the  general  formula  CsH2A2B2.  Of  these,  in  a given  case, 
thirteen  isomers  are  possible. 

Compounds  of  the  general  formula  CeH2ABC2.  Of  these,  in  a given  case, 
sixteen  isomers  are  possible. 

Compounds  of  the  general  formula  CeH2ABCD.  Of  these,  in  a given  case, 
thirty  isomers  are  possible. 

(d)  Pentasubstitution  products.  Compounds  of  the  general  formula 
CeHA5.  Of  these,  in  a given  case,  only  one  compound  has  been  recognized. 

Hexasubstitution  products.  Compounds  of  the  general  formula  C3A6.  Of 
these,  in  a given  case,  only  one  compound  has  been  recognized. 


Orientation  in  the  Benzene  Series. 

This  title  refers  to  the  assumed  position  in  the  benzene  ring  at 
which  combination  ensues  in  the  case  of  an  element  or  radicle 
substituted  for  a part  of  the  hydrogen  of  benzene. 


AROMATIC  COMPOUNDS. 


141 


\/: 

4 


The  actual  existence  of  a great  number  of  the  numerous  pos- 
sible isomers  just  referred  to  leads  of  necessity  to  the  conclusion 
that  they  owe  their  peculiar  differences  to  special  relative 
positions  (not  absolute  ones)  held  by  the  substituting  radi- 
cles. In  order  to  describe  the  relative  positions  in  the 
benzene  molecule  a definite  notation  has  been  adopted. 
It  is  customary  to  number  the  carbon  atoms  from  one  to 
six,  commencing  at  the  topmost  and  proceeding  round  in 
the  direction  of  clock  hands.  The  designations  of  the  several 
atoms  are  indicated  by  the  diagram. 

Monosubstitution  products.  It  has  already  been  proved  that  in 
mono  substitution  products  a single  atom,  substituted  for  hydrogen 
in  the  benzene  molecule,  may  take  equally  well  any  position  on 
the  ring. 

Disubstitution  products.  It  is  assumed  that  the  atoms  of  the 
substituting  element  may  occupy  the  positions  : 


1,  2,  or  1,  6,  called  ortho,  or  o. 

1,  3,  or  1,  5,  called  meta,  or  m. 

1,  4,  called  para,  or  p. 

/ 

The  assumption  has  in  this  case  been  borne  out  by  the  facts 
as  already  stated.  Indeed  the  preceding  proposition  as  to  the 
quality  and  the  chemical  force  of  the  carbon  atoms  in  the  benzene 
molecule  is  supported  by  the  results  in  the  case  of  disubstitution 
compounds. 

Trisubstitution  products.  Substituting  elements  or  radicles  may 
have  the  positions  : 


1,  2,  3,  called  consecutive. 
1,  3>  5>  called  symmetrical. 
1,  2,  4,  called  irregular. 


Tetrasubstitution  products.  Substituting  elements  or  radicles 
may  have  the  positions  : 

1,  2,  3,  4,  called  consecutive. 

1,  2,  4,  5,  called  symmetrical. 

1,  2,  3,  5,  called  irregular. 

P entasubstitution  products  and  hexasubstitution  products  will  be 
seen  to  fall  into  some  of  the  earlier  cases,  or  else  to  be  too  compli- 


142 


CARBON  COMPOUNDS. 


cated  for  further  discussion  here.  However  this  may  be,  they  are 
capable  of  discussion  in  accordance  with  the  numbering  system 
adopted. 

A Few  Examples. 

Reference  has  already  been  made  to  the  actual  existence  of 
three  isomers  in  case  of  disubstitution  compounds  like  dibrom- 
benzene  ; and  the  differences  have  been  shown  to  be  dependent 
upon  the  relative  positions  of  the  bromine  atoms.  The  follow- 
ing diagrams  represent  the  assumed  positions  : 


Br 

Br 

Br 

A- 

/\ 

A 

U 

U8r 

V 

Br 

i,  2,  Ortho,  o. 

i,  3,  Meta,  m. 

i,  4 Para,  p 

Now  the  truth  or  falsity  of  the  theory  represented  by  the  fore- 
going diagrams  may  be  estimated  by  introducing,  for  example, 
more  bromine  or  molecules  of  some  other  radicle  than  bromine. 
First,  upon  addition  of  more  of  the  same  element,  in  this  case, 
bromine,  the  ortho  compound,  is  capable  of  producing  two  iso- 
meric tribrombenzenes  ; the  meta  compound  can  afford  three 
isomeric  tribrombenzenes  ; the  para  compound  can  yield  only  one 
tribrombenzene.  This  state  of  things  may  be  be  more  clearly 
presented  by  the  following  diagrams  : 


Two  tribrombenzenes 
producible  from 
ortho-dibrombenzene 

Three  tribrombenzenes  producible 
from  meta-dibrombenzene 

One  tribrom- 
benzene pro- 
ducible from 
para-dibrom- 
benzene 

Br 

Br 

Br 

Br 

Br 

Br 

A«r 

MBr 

/y 

A 

/\ 

i/xr 

u- 

u 

Br 

\/L 

l> B 

Br 

vBr 

u 

Br 

I,  2,  3. 

1,  2,  4. 

i,  2. 3. 

1,  2,  4. 

(i>  3«  4-) 

3>  5- 

1,  2,  4. 

Only  three  different  compounds  are  represented  above. 


AROMATIC  COMPOUNDS . 


M3 


The  argument  acquires  greater  force  when  in  dibrombenzene 
the  group  N02,  called  nitroxyl,  is  added.  The  different  dibrom- 
benzenes  are  by  this  means  able  to  afford  only  two  isomers  for 
the  ortho  form,  three  isomers  for  the  meta  form,  and  one  com- 
pound for  the  para  form.*  These  results  may  be  made  more 
apparent  by  a consideration  of  the  following  diagrams  (all  for 
dibromnitrobenzene)  : 


Br 

Br 

Br 

Br 

Br 

Ab, 

/\.Br 

/\no2 

A 

A 

I I 

va* 

\/ 

U- 

IJb, 

NO  \/ 

N02 

no2 

1,2,3.  1,2,4. 


!,3,  2.  1,3,4. 


3’  5- 


1,  4,  2. 


A vast  number  of  other  benzene  derivatives  have  been  studied 
in  a similar  fashion,  and  the  facts  obtained  have  afforded  a suffi- 
cient basis  for  the  adoption  of  Kekule’s  or  some  similar  diagram 
for  benzene  and  also  for  the  acceptance  of  the  views  as  to  the 
ortho,  meta,  and  para  positions  heretofore  referred  to,  Moreover 
the  substitution  compounds  of  hydrocarbons  other  than  benzene 
have  been  subjected  to  a similar  kind  of  study,  and  from  them 
isomers,  showing  equally  pronounced  influence  of  relative  position 
in  the  molecule , have  been  produced. 

Again,  when  a given  di-isomer  is  under  investigation  the  ques- 
tion whether  it  is  an  ortho,  a meta,  or  a para  compound,  is  settled 
when  it  is  discovered  by  experiment  whether  it  can  produce  two 
or  three,  or  only  one  tri-isomer  respectively. 

Sources  of  Aromatic  Hydrocarbons. 

1.  Some  of  them  are  found  in  petroleum,  especially  the  Cau- 
casian and  the  Galician. 

2.  In  a few  cases  they  exist  ready-formed  in  plants. 

3.  They  may  be  produced  by  destructive  distillation  of 
wood  or  of  resin.  The  great  source  is  the  distillation  of  cannel 
coal  in  the  manufacture  of  illuminating  gas.  The  coal-tar  and 
the  various  naphthas  of  this  industry  contain  an  immense  number 
of  hydrocarbons  as  well  as  of  other  organic  substances. 


144 


CARBON  COMPOUNDS. 


Berthelot  has  observed  a most  interesting  fact ; namely,  that 
benzene  may  be  produced  by  a consolidation  of  acetylene  mole- 
cules. Thus : 

3C2H2  — CeHe 

Another  method  of  presenting  this  phenomenon  is  that  given 
by  Roscoe  and  Schorlemmer,  as  follows  : 


H 

I 

c 

m 

H— C C— H 

III 

H— C C— H 

C 

I 

H 


H 

I 

C 

^ \ 


H— C 

C— H 

1 

II 

H-C 

C— H 

/ 

c 

I 

H 


Still  other  aromatic  hydrocarbons  have  been  produced  in  a 
similar  way : indeed,  in  many  cases,  by  passing  vapors  of  the 
lower  hydrocarbons  through  red-hot  tubes,  higher  hydrocarbons 
may  be  produced.  It  is  believed  that  the  higher  hydrocarbons 
found  in  coal-tar  are  formed  from  the  lower  by  this  sort  of  mole- 
cular consolidation. 

4.  Special  aromatic  hydrocarbons  may  be  produced  by  definite 
chemical  reactions.  Thus  : 


C6H5Br  + CH3I  + 2Na  = C6H5CH3  -f-  NaBr  + Nal 
Monobrom-  Methyl  Metallic  Methyl  Sodium  Sodium 

benzene  iodide  sodium  benzene  bromide  iodide 


CHAPTER  XX. 


HYDROCARBONS  OF  THE  AROMATIC  SERIES. 

The  hydrocarbons  of  the  aromatic  group  form  several  separate 
series,  each  series  having  a general  formula  of  similar  type  to 
those  already  assigned  for  the  hydrocarbons  of  the  fatty  group. 
Each  series  may  have  many  members. 


Series  Formula 

First  Member 

Special  Formula 

Cn  H211 

Hexahydrobenzene, 

C2  H12 

Cn  H211— 2 

Tetrahydrotoluene, 

C7Hi2 

Cn  H2n— 4 

Dihydrobenzene, 

c6h8 

Cn  H2n-6 

Benzene, 

c6h6 

Cn  H2n— 8 

Phenylene, 

c6  h4 

Cn  H2n— 10 

Phenylacetylene, 

C8  H6 

Cn  H2n-12 

Naphthalene, 

CioHs 

Cn  H2n-14 

Biphenyl, 

C12H10 

Cn  H211-I6 

Acenaphthalene, 

Ci2H8 

Cn  H2n— 18 

Anthracene, 

C14  H10 

Cn  H2n— 20 

Fluoranthrene, 

C15  H10 

Cn  H2n-22 

Pyrene, 

C16H10 

Cn  H2n— 24 

Chrysene, 

Cl8  H12 

Cn  H2n-26 

Phenylanthracene, 

C20  H14 

Cn  H2n— 28 

Dinaphthylethylene, 

C22  Hi6 

Cn  H2n— 30 

Dinaphthylacetylene, 

C22  H14 

Cn  H2n-32 

Dinaphthylanthrylene, 

C22  H12 

Cn  H2n-34 

Dinaphthyldiacetylene, 

C24  H14 

Cn  H2n-36 

Dibiphenylene-ethene, 

C26  Hi6 

Cn  H2n— 38 

C26  H14 

Cn  H2n— 40 

Carbopetrocene, 

C24  Hs 

10 


045) 


146 


CARBON  COMPOUNDS. 


Hydrocarbons  of  the  Benzene  Series,  CnH2n-e* 

Above  one  hundred  hydrocarbons,  of  this  special  series,  are 
known.  A few  are  mentioned  below  : 


Benzene, 

Toluene, 

c6h6 

c7h8 

c6h5-ch3 

Ethylbenzene, 

Xylene, 

C8Hio 

c6h5-c2h5 

C6H4(CH3)2 

Propylbenzene, 

Cumene, 

Mesitylene, 

C9Hi2 

c6h5-c3h7 

C6H5-CH(CH3)2 

c6h3cch3)3 

f 8 comps. 
t known,  j 

Normal  butyl  benzene, 
Cymene, 

C10H14 

C6H5-C4H9 

CH3-C6H4-CH(CH3)2 

j 24  comps. ) 
1 known,  J 

Normal  amylbenzene, 

CnH16 

C6H5-C5Hn 

(21  known) 

Many  others,  up  to 

C25H44 

1.  A mere  inspection  of  the  above  list  shows  that  many 
isomers  are  possible. 

2.  Several  of  the  compounds  mentioned  contain  molecules  in 
which  an  aromatic  group  and  a fatty  group  are  united.  This  is 
significant.  In  substitution  compounds  from  such  molecules,  if 
replacement  occurs  in  the  benzene  nucleus,  then  the  compound 
formed  shows  aromatic  relationships  ; but  if  replacement  occurs 
in  the  fatty  side-chain,  the  compound  formed  has  properties  of  a 
fatty  character. 

3.  Many  of  these  compounds  are  found  in  coal  tar.  Many  of 
them  are  producible  artificially. 

Benzene , C6H6.  Benzene  occurs  in  small  quantities  in  nature 
in  certain  petroleums,  especially  those  of  Burma  and  Galicia. 

It  is  produced  artificially  by  the  destructive  distillation  of 
cannel  coal,  of  wood,  and  of  many  other  organic  substances. 

Reference  has  already  been  made  to  its  production  by  the 
heating  of  certain  other  hydrocarbons,  even  those  of  the  fatty 
groups,  for  example  its  synthetic  production  from  acetylene, 
C2H2. 

The  supply  of  the  substance  for  commerce  is  mainly  from  the  coal-tar  pro- 
duced in  the  manufacture  of  illuminating  gas.  This  tar  collects  in  certain  of 
the  condensers  and  wells,  and  is  afterwards  separated.  It  contains  apparently 
hundreds  of  different  substances;  only  a few  of  them,  however,  are  as  yet  of 


AROMATIC  HYDROCARBONS. 


147 


importance.  From  it  are  carefully  separated  benzene,  toluene,  anthracene,  and 
a few  others. 

For  the  separation  of  benzene,  the  coal-tar  is  introduced  into  enormous  iron 
retorts  or  stills.  The  contents  of  the  retorts  being  heated,  a rough  fractional 
distillation  is  accomplished.  The  fractions  obtained  are  of  three  or  four  different 
grades.  That  called  “ first  runnings  ” contains  considerable  benzene  mixed, 
however,  with  other  substances.  The  next  portion  collected  is  called  “ light 
oil,”  or  “ crude  naphtha.”  Another  portion,  later  collected,  is  called  “ middle 
oil.”  Another  portion,  later  collected,  is  called  “heavy  oil,”  or  “ dead  oil.” 
'This  portion  is  often  separated  into  two  portions,  the  one  called  creasote  oil 
and  the  other  anthracene  oil.  Finally,  there  is  left  in  the  retort  a heavy  mass 
(having  a high  boiling  point)  called  pitch. 

The  second  fraction  called  “ light  oil,”  is  the  portion  from  which  the  different 
kinds  of  benzene  are  obtained.  This  oil  is  subjected  to  a more  careful  fractional 
distillation  and  thus  made  to  afford  benzene,  somewhat  impure,  but  of  better 
quality  than  that  originally  obtained.  It  also  furnishes  toluene  and  several 
other  hydrocarbons. 


At  ordinary  temperatures  benzene  is  a colorless  liquid  possess- 
ing a characteristic  odor.  It  burns  with  a luminous  but  smoky 
flame.  It  is  distinctly  poisonous.  Notwithstanding  its  large 
number  of  carbon  atoms  it  has  a relatively  stable  molecule.  Yet 
it  easily  undergoes  a very  large  number  of  chemical  changes 
whereby  one  or  several  of  the  hydrogen  atoms  in  the  molecule 
are  replaced  by  other  radicals. 

Its  chief  use  in  the  arts  is  in  the  production  of  nitro-benzene 
and  thence  aniline  and  the  various  aniline  colors. 

Toluene , or  methyl  benzene , C7H8,  or  C6H5CH3.  This  is  the  sec- 
ond member  of  the  benzene  series,  and  it  is  often  found  associ 
ated  with  benzene  in  operations  leading  toward  the  production  of 
the  latter.  Thus,  it  is  produced  by  the  distillation  of  resin,  espe- 
cially that  contained  in  balsam  of  Tolu.  This  latter  substance  is 
obtained  in  the  district  of  Tolu  in  the  neighborhood  of  Cartagena 
in  New  Granada,  South  America.  The  balsam  is  obtained  by 
means  of  incisions  in  the  trunk  of  a large  tree,  myrospermum  tolu - 
iferum.  The  juice  which  exudes  hardens  into  reddish  brown 
masses. 

Toluene  is  ordinarily  obtained  from  the  oils  of  coal  tar  which 
contain  benzene.  The  benzene  and  toluene  are  separated  by  frac- 
tional distillation  as  already  stated  in  another  place. 

Toluene  is  a liquid  somewhat  resembling  benzene.  Like  the 
latter  substance,  it  is  capable  of  forming  a very  large  number  of 


148 


CARBON  COMPOUNDS. 


compounds,  many  of  which  have  been  carefully  studied.  Thus,  it 
forms  various  chlorine  and  bromine  substitution  compounds.  It 
also  forms  important  nitro  compounds. 

The  following  series  of  hydrocarbons  is  interesting.  It  sug- 
gests, however,  a large  number  of  other  compounds  producible,  in 
similar  fashion,  by  further  replacement  or  different  positions  of  the 
same  or  different  fatty  radicles  in  a single  benzene  nucleus  or  even 
in  other  hydrocarbons  having  more  than  one  benzene  nucleus  in  the 
molecule. 


o-Xylene, 


H 

H 

HCH 

HCH 

ASh 

A 

lH 

m-Xylene,  ** 

\/ 

\/H 

H 

HCH 


p-Xylene, 


HCH 

H 


H 

HCH 


/ 


-2-3  Cumene, 


\/ 


H 

CH 

H 

H 

CH 

H 


1-3-5  Mesitylene, 


H 

HCH 

A 

HI  H 
HC|  |CH 
H\/H 


1-2-3-4  Cymene,  (durene) 


H 

HCH 


V 

HCH 

H 


H 

CH 

H 

H 

C H 
H 


Hydrocarbons  of  the  formula  C12H18.  (14  compounds  known.) 

The  substance  mellitene,  which  is  hexmethylbenzene,  has  the 
rational  formula  C6(CH3)6.  This  formula  itself  is  a very  simple 
and  interesting  illustration  of  the  power  of  substitution  of  the 
organic  radicle  methyl.  The  formula  really  represents  a molecule 
of  benzene,  C6H6,  in  which  every  atom  of  hydrogen  has  been 
replaced  by  the  radicle  methyl,  CH3.  The  substance  itself  has 
been  produced  by  a variety  of  chemical  operations  ; among  others, 
by  the  reaction  of  certain  chemical  compounds,  including  methyl 
compounds  and  benzene. 


AROMATIC  HYDROCARBONS. 


149 


Hydrocarbons  of  the  Naphthalene  Series,  C11H211-12. 

About  twenty  hydrocarbons  of  this  series  are  known.  The 
most  important  is  naphthalene. 

Naphthalene , C10H8.  This  substance,  at  ordinary  temperatures, 
is  a white  crystalline  solid.  It  is  produced  in  considerable  quan- 
tities by  the  distillation  of  cannel  coal  in  the  manufacture  of 
illuminating  gas.  It  has  long  been  a source  of  great  annoyance 
to  gas  manufacturers.  Occasionally,  for  some  unexplained  reason, 
the  naphthalene  has  been  able  to  pass  all  the  various  condensers  of 
the  gas  works  and  find  its  way  in  considerable  quantities  into  the 
distribution  pipes.  There  it  has  sometimes  condensed  in  such 
amounts  as  to  clog  the  pipes  and  seriously  interfere  with  the  dis- 
tribution of  the  gas. 

It  is  formed  in  many  cases  where  organic  substances  are  sub- 
jected to  destructive  distillation,  especially  when  the  vapors  so 
produced  are  highly  heated  as  they  pass  through  tubes. 

The  naphthalene  molecule  is  believed  to 
represent  a consolidation  of  two  benzene  nu- 
clei, as  represented  in  the  upper  diagram  in 
the  margin.  But  it  is  usually  represented  in 
the  abridged  form  given  in  the  lower  diagram 
(only  without  the  numbers). 

The  numerous  isomers  of  naphthalene  deriva- 
tives have  been  carefully  studied.  As  a result, 
the  following  view  has  been  formulated  : when 
a single  radicle,  R,  is  substituted  for  hydrogen 
in  naphthalene,  it  may  form  one  of  two  com- 
pounds, according  to  its  position  on  the  ring ; 
if  it  occupies  either  of  the  positions,  1,  ir,  4,  4' 
it  produces  what  is  called  an  alpha  compound 
(often  designated  by  a prefixed  to  the  name)  ; 
if  it  occupies  either  of  the  positions  2,  2',  3,  3', 
it  produces  what  is  called  a beta  compound 
{often  designated  by  /3  prefixed  to  the  name.) 

(Several  notations,  other  than  that  indicated  by  the  numbering 
shown  on  the  margin,  have  been  suggested ; it  is  thought  that  the 
numbering  here  employed  has  distinct  advantages.) 


H H 
C C 

S \ / % 


HC 

C 

II 

CH 

1 

HC 

II 

c 

CH 

% / \ // 
c c 

H H 
Naphthalene, 
CioH8 


A 

I I 


4"  4 


CARBON  COMPOUNDS. 


150 


a-naphthol  /3-naphthol  a-nitronaphthalene  /3-nitronaphthalene 


Hydrocarbons  of  the  Anthracene  Series,  CnH2n-i8. 

About  thirty-two  hydrocarbons  of  this  series  are  known.  The 
most  important  is  anthracene. 

Anthracene , C14H10.  This  hydrocarbon  was  long  ago  recognized 
as  a constituent  of  coal-tar.  It  was  formerly  considered  as  a 
worthless  substance,  being  used  as  a lubricant  under  the  name  of 
g^een  grease.  But  Graebe  and  Liebermann  showed  that  alizarin, 
the  chief  dyeing  material  in  madder,  might  by  reducing  processes 
yield  anthracene.  Thereupon  they  perceived  that  if  alizarin  could 
yield  anthracene,  anthracene  might  be  turned  into  alizarin.  They 
succeeded  in  accomplishing  the  desired  achievement.  The  proc- 
ess of  manufacturing  alizarin  from  anthracene  has  since  been 
cheapened  so  that  artificial  alizarin  is  now  largely  used  in  dyeing 
and  calico  printing. 

The  structural  formula  of  anthracene  may  be  considered  as 
that  of  ethane,  in  which  two  pairs  of  hydrogen  atoms  have  been 
replaced  by  two  benzene  rings. 


H 

HCH 

I 

HCH 

H 


\/Lch-' 


\ 


Ethane,  C2H6 


Anthracene,  C14H10 


The  importance  of  the  manufacture  of  artificial  alizarin  has  led 
to  the  careful  collection  of  the  largest  possible  amount  of  anthra- 
cene from  coal-tar. 

Anthracene  when  pure  is  a white  solid,  forming  glistening, 
crystalline  scales.  It  does  not  dissolve  in  water.  It  dissolves  in 
certain  organic  liquids,  like  alcohol,  ether,  chloroform,  carbon 
disulphide,  light  petroleum,  hydrocarbons,  etc.  It  dissolves  in 
much  larger  quantity  in  toluene. 

Anthracene  forms  an  insoluble  red  picrate,  with  alcoholic  solu 
tion  of  picric  acid. 

Oxidizing  agents  turn  anthracene  in  anthraquinone. 

Sulphuric  acid  produces  sulphonic  acids. 


CHAPTER  XXI. 


CERTAIN  SPECIAL  AROMATIC  HYDROCARBONS. 

Terpenes,  Etc. 

A number  of  hydrocarbons  having  the  common  formula  C10H16, 
or  some  multiple  of  it,  have  been  recognized.  They  find  their 
chief  representatives  in  certain  constituents  of  turpentine,  in  cer- 
tain etherial  oils  such  as  oil  of  lemons  (and  oils  of  other  odorif- 
erous vegetable  matters)  substances  having  the  formula  C10H16,  or 
some  multiple  of  it.  These  hydrocarbons  are  closely  related  to 
camphor  and  also  to  gutta  percha  and  caoutchouc  (India  rubber.) 

Terpenes.  The  vegetable  substances  analogous  to  turpentine 
appear  to  contain  a number  of  different  substances.  These  are 
thought  to  be  represented  by  the  following  groups : 

ist  Group.  2d  Group.  3d  Group. 

Pinene,  Limonene,  Terpinene, 

Camphene.  Dipentene,  Phellandrene. 

Sylvestrene, 

Terpinolene. 

While  the  formulas  of  these  substances  have  not  been  well 
made  out,  the  following  may  be  presented  : 


ch3 

ch3 

1 

1 

C 

1 

c 

/ \ 

/ w 

h2c 

CH 

HC  CH 

1 

II 

l\l 

h2c 

CH 

H2C  CH 

\ 

/ 

\ / 

( 

CH 

C3H7 

| 

C3H7 

Camphene, 

Pinene, 

CioPhe 

CioHi6 

152 


CARBON  COMPOUNDS. 


Oil  of  Turpentine.  This  substance  is  largely  produced  in  the 
United  States,  especially  in  North  Carolina,  from  the  pine  tree  of 
that  region,  pinus  australis.  Oil  of  turpentine  as  found  in  com- 
merce is  a composite  substance  containing  not  only  hydrocarbons 
but  certain  oxidation  products.  The  substance  has  a consider- 
able affinity  for  oxygen,  absorbing  the  latter  from  the  air  and  thus 
becoming  thick  and  gummy.  The  action  of  chlorine  gas  upon 
oil  of  turpentine  is  well  known.  At  ordinary  temperatures  the 
two  substances  react,  the  chlorine  combining  with  hydrogen  and 
producing  flame,  while  large  quantities  of  the  carbon  escape  in 
the  form  of  a black  smoke.  Incidentally,  however,  chlorine  com- 
bines with  the  radicles  present,  producing  chlorine  substitution 
compounds. 

Turpentine.  The  turpentine  industry  of  the  United  States  is  practically  con- 
fined to  a belt  of  about  one  hundred  miles  in  width  along  the  Atlantic  and  Gulf 
coasts,  from  North  Carolina  to  Louisiana.  The  importance  of  the  industry 
may  be  recognized  from  the  considerable  annual  value  of  the  product,  nearly 
$10,000,000.  But  the  influence  this  industry  exerts  on  the  condition  of  the 
forests  involved  must  not  be  overlooked.  The  securing  of  so-called  naval 
stores , this  term  including  all  the  resinous  products  and  their  derivatives  gath- 
ered from  coniferous  trees,  has  been  conducted  in  a very  wasteful  and  careless 
manner.  Indeed,  considering  the  crude  methods  employed  and  the  disastrous 
incidental  conflagrations,  which  destroy  vast  areas  of  valuable  timber,  this 
industry  has  been  declared  to  be  one  of  the  most  unprofitable,  all  things  con- 
sidered, carried  on  by  this  country. 

The  name  employed,  naval  stores,  is  due  to  the  fact  that  the  largest  consump- 
tion of  these  products  is  referable  to  ship  construction  and  ship  management. 
Of  course  the  increasing  use  of  iron  in  ship-building  tends  to  release  a some 
what  increasing  proportion  of  naval  stores  for  other  industries. 

In  securing  turpentine  from  the  tree  different  methods  are  employed.  In 
some  cases  a scar  or  other  incision  is  formed  upon  the  tree.  The  liquid  may 
flow  into  vessels  or  may  dry  in  the  form  of  resinous  lumps  upon  surfaces. 
In  other  cases  bore-holes  are  made  and  the  resinous  material  may  be  collected 
in  the  heart  of  the  wood.  It  is  said  that  a prejudice  has  long  existed  against 
timber  obtained  from  trees  that  have  been  tapped  or  bled.  Recent  thorough 
investigations  have  shown  that  this  prejudice  is  not  justified  by  facts. 

The  chief  products  of  the  turpentine  industry  are  the  following: 

First.  Resin  or  crude  turpentine.  This  is  the  crude  material  obtained  by  tap- 
ping or  bleeding  the  trees.  It  is  a mixture  of  resinous  material  and  oil  of  tur- 
pentine, the  latter  holding  the  resins  partly  in  solution,  partly  in  suspension. 
The  material  varies  very  much  in  quality;  in  some  cases  being  liquid,  in  others 
semi-liquid  or  solid.  In  color  these  original  resins  vary  from  yellow  to  dark 
brown.  Even  the  more  liquid  ones  harden  on  exposure  to  the  air. 

Second.  Spirits  of  turpentine,  or  oil  of  turpentine.  This  is  a liquid  distillate 
from  the  crude  resin.  When  pure  it  is  a mixture  of  hydrocarbons  of  the  gen- 


TER  PENES,  ETC. 


iS3 


eral  formula  Cio  H16.  The  impure  product,  as  obtained  from  the  still,  contains 
however  other  hydrocarbons  and  acids.  By  further  distillation  a purer  spirit  of 
turpentine  may  be  obtained.  This  product  is  used  in  the  arts  mainly  for  the 
preparation  of  varnishes  and  paints,  and  in  the  rubber  industry.  It  has  had 
considerable  use  in  the  preparation  of  an  illuminating  oil — the  liquid  material 
formerly  well  known  under  the  name  of  camphene.  Spirit  of  turpentine  has 
also  wide  use  in  certain  medicinal  preparations. 

Third.  Rosin , or  colophony.  When  crude  turpentine  is  distilled  for  the  pro- 
duction of  spirit  of  turpentine,  a residue  is  left  in  the  retort.  This  residue 
hardens  upon  the  cooling  incidental  to  withdrawal.  It  may  be  transparent  or 
almost  opaque.  It  may  be  pale  yellow  or  deeper  shades,  almost  to  black. 
Sometimes  it  is  tolerably  soft,  sometimes  very  hard.  This  rosin  is  used  in  the 
manufacture  of  varnish,  sealing-wax,  putty,  soap,  paper,  in  certain  bleaching 
operations,  and  for  the  preparation  of  subordinate  products. 

When  rosin  is  submitted  to  dry  distillation,  at  least  three  products  are 
obtained. 

The  first  product,  called  light  rosin  oil,  is  used  in  the  manufacture  of  var- 
nishes. 

The  second  product,  called  heavy  rosin  oil,  is  used  in  the  manufacture  of 
printers’  ink,  machine  oil,  axle  grease,  etc. 

The  third  product  is  called  common  pitch.  It  is  a glossy,  black,  brittle  sub- 
stance. It  is  used  in  a variety  of  forms  for  waterproofing  purposes. 

Fourth.  Brewers'  pitch.  This  substance  is  obtained  when  crude  turpentine 
is  distilled  incompletely;  that  is,  before  the  oil  has  all  been  expelled.  This  oil 
of  turpentine  remaining  gives  the  brewers’  pitch  certain  desirable  qualities ; 
enables  it,  for  example,  to  adhere  to  a surface  to  which  it  is  applied.  The  best 
quality  of  this  product  is  obtained  from  the  larch  and  is  produced  mostly  in  the 
Tyrol. 

Brewers’  pitch  is  used  for  smearing  the  inner  surface  of  beer  kegs. 

Fifth.  Tar.  This  substance  is  not  exactly  a by-product  of  the  turpentine 
orchard.  On  the  contrary,  it  is  a product  of  destructive  distillation  of 
a wood  juice.  Commercial  tar  is  still  and  has  been  for  a long  time  chiefly 
produced  in  North  Carolina.  Certain  portions  of  perfectly  dry  wood  are  cut 
into  suitable  billets,  then  piled  into  a conical  stack  in  a circular  pit  lined  with 
clay.  The  pile  is  covered  with  sod  and  earth  and  at  length  is  fired  by  means  of 
passages  or  apertures  at  the  base.  A slow,  smoldering  combustion  is  main- 
tained. After  the  ninth  or  tenth  day  the  flow  of  tar  begins  and  continues  for 
several  weeks.  The  tar  is  dipped  from  the  pit  and  transferred  to  barrels. 

Sixth.  Oil  of  tar.  This  is  obtained  by  distillation  of  the  tar.  It  is  a complex 
mixture  containing  hydrocarbons,  some  wood  alcohol,  a small  quantity  of  creo- 
sote, certain  empyreumatic  substances.  It  is  used  both  as  an  insecticide  and  in 
certain  crude  forms  of  medical  practice. 

Camphor , C10H16O.  This  valuable  resin  is  obtained  in  Formosa 
from  the  camphor  tree,  laurus  camphora,  which  grows  in  many 
regions  in  the  Orient.  The  camphor  is  obtained  from  the  tree  by  a 
very  coarse  and  wasteful  method.  The  wood  being  cut  into  suit- 


154 


CARBON  COMPOUNDS . 


able  billets  is  subjected  to  the  action  of  heat  and  steam  in  such  a 
way  that  the  camphor  is  expelled  and  afterwards  collected  in  earthen 
jars.  Subsequently,  the  raw  camphor  is  subjected  to  more  care- 
ful distillation  in  order  to  produce  the  white  material  commonly 
seen  in  civilized  countries. 

Different  structural  formulas  have  been  proposed  for  camphor. 
The  following  is  the  result  of  recent  studies : 

H H H 

HC C CH 

H | H 

HC— C—  CH 
H | H 

HC C CO 

H | 

HCH 

H 

Camphor  volatilizes  at  ordinary  temperatures.  A small  amount 
placed  at  the  bottom  of  a bottle  will  in  time  transfer  itself  by 
volatilization  and  condensation  to  the  upper  part  of  the  same  ves- 
sel. Its  pungent  odor  is  another  evidence  of  its  volatilizing. 

A curious  and  well-known  experiment  is  now  believed  to  be  dependent  upon 
this  same  tendency  to  volatilize;  namely,  when  fragments  of  camphor  are 
thrown  upon  clean  water,  they  at  once  set  up  a very  active  rotation  upon  the 
surface  of  the  liquid.  If  a needle  or  glass  rod  or  other  substance  having  a very 
minute  amount  of  oil  upon  it,  is  plunged  into  the  upper  layers  of  the  water,  the 
rotation  of  the  gum  instantly  ceases.  It  is  believed  that  the  rotation  is  due  to 
the  rapid  vaporization  of  the  camphor  upon  certain  sides,  and  that  the  vapor 
pressure  produces  a reaction  which  leads  the  granules  to  rotate  in  a contrary- 
wise  direction.  It  is  supposed  that  the  oil  spreads  in  a thin  film  over  the  frag- 
ments of  the  camphor  and  thus  prevents  evaporation. 

Caoutchouc , or  India  rubber , (C10H16)n.  It  has  long  been  the 
custom  of  natives  of  certain  parts  of  South  America  to  obtain  the 
gum  called  caoutchouc  from  certain  native  trees.  The  method 
employed  in  general  has  been  to  perforate  the  bark  of  the  tree 
and  then  collect  in  a convenient  vessel  the  milky  juice  which 
flows  freely.  Into  this  juice  the  natives  dip  some  sort  of  wooden 
mold.  When  the  mold  is  coated  with  a thin  film,  the  latter  is 
heated  over  an  ordinary  fire.  The  film  soon  hardens,  and  then 
another  is  produced  in  a similar  manner  outside  of  it.  The 
process  is  repeated  until  a sphere,  about  six  inches  in  diameter, 
is  produced.  By  and  by  the  film  is  removed  from  the  wooden 
former,  and  is  sent  into  commerce  as  what  is  called  a bottle. 


CAOUTCHOUC. 


155 


Vegetable  juices  containing  rubber,  or  similar  hydrocarbons, 
are  cured  in  other  ways  in  some  parts  of  the  world  : by  drying  in 
the  sun  ; by  boiling  in  kettles ; by  mixing  with  brine,  alum,  etc. 

The  best  rubber  comes  from  the  district  of  Para  on  the  lower  Amazon,  but 
rubber  of  similar  character  is  produced  from  the  milky  juice  of  many  kinds  of 
trees  growing  in  many  parts  of  the  world.* 

Rubber  is  classified  in  trade  as  Paras  (from  Brazil),  Centrals  (from  Central 
America),  Africans  (from  many  points  on  that  continent  and  its  adjacent 
islands),  East  Indians  (from  regions  in  and  about  India). 

Paras  are  classified  as  fine  new,  fine  old,  medium,  coarse  new,  coarse  old, 
upriver  fine,  upriver  coarse,  Caucho,  Ceara,  Peruvian,  Bolivian,  Matto-Grosso, 
Manoa,  Mangabeira  (Bahia). 

Centrals  are  classified  as  Esmeralda,  Guayaquil,  Nicaragua,  Cantagena. 

East  Indians  are  classified  as  Borneo,  Assam,  Penang,  Pontianak,  Siam, 
Padang  (Sumatra). 

Africans  are  classified  as  St.  Paul  de  Loando,  Gambia,  Sierra  Leone,  Ben- 
guela,  Kongo,  Cameroon,  Accra,  Liberian,  Madagascar  pinky  or  black,  Calabar, 
old  Calabar,  Batanga,  Salt  Pond  (Cape  Coast),  Mozambique,  Akassa. 

According  to  the  for7n  of  the  raw  commercial  products  they  are  named  as 
strip,  scrap,  slab,  sheet,  flake,  lump  flake,  liver,  ball,  small  ball,  sausage, 
thimble,  twist,  nigger. 

Pure  caoutchouc  is  light  in  color.  It  is  darkened  by  the  crude 
methods  adopted  in  its  first  stages  of  manufacture.  It  has  been 
proposed  to  receive  in  metallic  vessels  the  juice  as  it  flows  from 
the  tree ; then,  sealing  the  vessels,  to  send  them  to  the  United 
States  or  to  Europe  for  more  intelligent  treatment  of  the  gum. 
Ordinary  caoutchouc  is  very  adhesive,  freshly  cut  portions  join- 
ing very  rapidly.  When  heated  moderately,  it  melts  into  a viscid 
mass.  At  high  temperatures  it  undergoes  decomposition,  evolv- 
ing gases,  which  easily  take  fire  and  burn  with  a luminous  but 
smoky  flame.  Caoutchouc  does  not  readily  dissolve,  but  it 
softens  in  certain  liquids  of  which  carbon  disulphide  is  one  of 
the  best.  Coal-tar  naphthas  of  various  kinds,  and  benzene,  are 
among  the  best  solvents.  (See  isoprene,  p.  46.) 

Europeans  appear  to  have  had  their  attention  attracted  to  caoutchouc  first  in 
1736  by  La  Condamine,  who  was  a member  of  a commission  sent  by  the  French 
government  to  measure  a degree  of  the  meridian  in  South  America.  He  sent 
to  France  some  samples  of  caoutchouc  under  the  name  of  gum  elastic.  He 
noted  that  the  material  was  employed  by  the  people  of  Brazil  for  use  not  only 
in  torches  but  also  for  bottles,  overshoes,  waterproof  fabrics,  and  even  rude 
syringes.  In  Europe  the  caoutchouc  soon  came  into  use  by  artists  and  others 


See  U.  S.  Special  Consular  Report.  India  Rubber.  Washington,  D.  C.,  1892. 


156 


CARBON  COMPOUNDS. 


for  erasing  pencil  marks.  The  English  chemist  Priestley,  in  one  of  his  essays, 
speaks  of  the  substance  in  connection  with  the  last  mentioned  use. 

In  1797,  an  English  manufacturer  named  Johnson  patented  a process  for  mak- 
ing cloth  waterproof  by  the  use  of  rubber.  He  softened  the  material  in  a mix- 
ture of  turpentine  and  alcohol,  and  spread  the  paste  so  produced  upon  cloth. 
He  even  went  farther,  in  that  he  spread  over  the  gummy  surface  the  fine  textile 
powder  known  as  “ flocks.” 

In  1819,  a Scotch  manufacturer,  Macintosh  by  name — who  was  using  large 
quantities  of  ammoniacal  liquors  from  gas  works  and  was  seeking  a commercial 
outlet  for  the  naphtha  of  the  gas  manufacture — conceived  the  idea  of  using  this 
naphtha  as  a solvent  for  caoutchouc,  intending  to  spread  the  varnish  so  pro- 
duced upon  cloth,  thereby  rendering  it  waterproof. 

In  1825,  rude  overshoes  of  caoutchouc  were  brought  'to  the  United  States  from 
Brazil,  many  of  them  made  upon  lasts  shipped  from  Boston.  Large  quantities 
of  such  galoshes*  were  exported,  notwithstanding  the  fact  that  they  were  of  a 
very  rude  shape  and  that  they  became  very  soft  when  exposed  to  heat  and  very 
hard  when  cooled. 

The  greatest  improvement  in  the  treatment  of  India  rubber  was  that  invented 
by  Charles  Goodyear  and  patented  by  him  in  1844;  namely,  the  process  called 
vulcanizing.  Goodyear  observed  that  when  caoutchouc  is  mixed  with  sulphur 
and  the  mass  heated,  the  properties  of  the  substance  are  materially  changed. 
The  small  amount  of  sulphur,  say  five  or  ten  per  cent.,  enables  the  rubber 
article,  while  still  preserving  the  valuable  property  of  being  impervious  to 
water,  to  retain  its  pliability  when  cold.  This  is  the  general  principle  still 
underlying  the  vulcanizing  process.  Goodyear  also  noted  that  a much  larger 
amount  of  sulphur,  say  fifty  per  cent.,  produces  the  article  now  well  known  as 
hard  rubber  or  ebonite.  This  substance  is  now  very  much  employed  for  an 
immense  variety  of  articles  of  daily  use.  One  of  its  most  valuable  properties 
from  the  scientific  point  of  view,  is  the  fact  that  when  briskly  rubbed  with  cer- 
tain dry  materials,  it  becomes  highly  electrified. 

At  the  present  day,  vast  quantities  of  caoutchouc  products  are 
employed  in  manufactures.  Hard  rubber  is  employed  for  a mul- 
titude of  small  articles,  like  buttons,  penholders,  combs,  handles 
for  various  pieces  of  apparatus.  The  characteristic  valuable  qual- 
ities of  hard  rubber  are  cleanliness,  imperviousness  to  liquids, 
elasticity,  lightness  as  compared  with  metals,  and  finally  a certain 
ease  of  manufacture. 

The  characteristic  qualities  of  ordinary  vulcanized  rubber  are 
great  imperviousness  to  liquids  and  gases,  high  insulating  power 
for  electrical  appliances.  This  variety  of  rubber  has  so  many  and 
such  well  known  uses  that  it  is  unnecessary  to  specify  them. 

In  general,  the  process  of  manufacture  of  rubber  articles,  such 
as  boots  and  shoes,  is  as  follows  : 


The  word  galoche  occurs  in  Piers  Plowman.  Chaucer  says  “ unbokel  his  galoche.' 


CAOUTCHOUC . 


157 


First,  the  gum  is  washed  by  soaking  in  hot  water  and  subse- 
quently passing  it  between  rollers  under  a small  stream  of  water. 

Second , it  is  sheeted  by  passing  it  through  another  set  of  power- 
ful rollers.  As  a result  it  forms  a coherent  but  irregular  sheet. 

Third,  it  is  dried , to  remove  all  moisture. 

Fourth , it  is  compounded , that  is,  it  is  again  passed  between 
another  set  of  powerful  rollers,  in  presence  of  certain  substances 
to  be  mixed  with  it.  The  latter  may  be  looked  upon  as  either 
mere  diluents,  or  adulterants,  or  coloring  matters,  or,  it  may  be, 
sulphur  to  accomplish  the  vulcanizing.  Oxide  of  zinc,  a white 
powder,  may  be  used  to  produce  light  colors ; sulphide  of  anti- 
mony, to  produce  red  colors ; lamp  black,  to  darken  ; second- 
hand rubber  goods,  to  cheapen.  In  this  process,  the  rolls  between 
which  the  rubber  passes  revolve  at  different  rates  of  speed. 
Thus,  the  mixture  is  worked  out  into  thinner  and  thinner  sheets. 

Fifth , from  the  sheets  just  mentioned,  the  manufactured  arti- 
cle, say  a rubber  boot,  may  be  formed,  the  different  portions 
being  cemented  together. 

Sixth , the  object  is  placed  in  a suitable  oven  to  be  vulcanized. 

Seventh,  before  going  into  the  market,  the  article  may  be  var- 
nished. 

Rubber  goods  for  mechanical,  medical,  and  other  uses,  are  made 
by  but  slightly  different  processes. 

Gutta  percha , although  resembling  caoutchouc  in  some  respects, 
such  as  capacity  for  resisting  liquids,  and  capability  of  vulcanizing 
under  the  influence  of  sulphur  and  heat,  is  a very  different  mate- 
rial from  India  rubber.  It  is,  however,  derived  from  the  juice  of 
a tree  ( isonandra  percha),  and  in  its  manufacture  and  treatment, 
much  resembles  India  rubber.  Gutta  percha  comes  from  the 
Orient,  especially  from  Singapore  and  Borneo. 

Gutta  percha  is  not  produced  in  such  considerable  quantities  as 
is  India  rubber.  It  is  far  superior  to  the  latter,  however,  as  an 
electric  insulating  material.  Naturally,  therefore,  the  modern 
development  of  electricity  has  largely  increased  the  demand  for 
the  substance. 

Batata  is  a valuable  vegetable  product  somewhat  analogous  to 
gutta  percha.  It  is  obtained  from  South  America.  It  may  be 
rolled  into  thin,  colorless,  odorless  sheets,  and  used  for  water- 
proofing purposes  without  vulcanizing. 


CHAPTER  XXII. 


AROMATIC  SUBSTITUTION  COMPOUNDS. 

Halogen  Derivatives. 

The  aromatic  hydrocarbons  form  an  immense  number  of  halo- 
gen derivatives  with  fluorine,  chlorine,  bromine,  and  iodine. 
Some  have  been  referred  to  already. 

From  benzene,  C6H5,  may  be  formed  C6H5C1,  C6H4C12,  C6H3C13, 
C6H2C14,  C6HC15,  C6C16,  and  some  of  these  form  isomers.  In 
similar  fashion  other  hydrocarbons  form  derivatives  more  numer- 
ous and  more  complex ; for  halogen  substitution  may  take 
place  in  the  benzene  nucleus,  or  in  the  fatty  side-chain,  or  in  both  at 
once,  or  in  one  or  more  benzene  rings  of  composite  hydrocarbons  of 
higher  series. 

Aromatic  Nitro-Derivatives. 

Nitrobenzene,  C6H5N02.  This  substance  is  easily  produced  by 
the  action  of  fuming  nitric  acid  upon  benzene.  Considerable 
heat  is  evolved  by  the  operation,  and  it  is  usual  in  the  manufac- 
ture to  keep  the  mixture  at  a low  temperature.  The  mixing  is 
usually  carried  on  in  large  iron  retorts  supplied  with  mechanical 
stirrers.  The  nitrobenzene  produced  is  then  run  into  water, 
whereby  any  excess  of  acid  is  dissolved  in  the  water ; the  nitro- 
benzene falls  to  the  bottom  of  the  vessel,  from  which  it  may  be 
drawn  off.  Generally  it  is  subjected  to  other  washings  and  finally 
to  distillation  which  affords  the  substance  in  a comparatively  pure 
form. 

Nitrobenzene  is  a yellow  liquid  having  a very  strong  and  rather 
agreeable  odor  of  bitter  almonds.  It  is  sometimes  called  “essence 
of  mirbane,”  and  as  such  is  considerably  employed  in  toilet  soaps. 
The  substance,  if  inhaled  in  large  quantity  as  vapor,  or  if  taken 
into  the  digestive  tract,  is  distinctly  poisonous.  Enormous  quan- 


AROMATIC  DERIVATIVES. 


159 


tities  of  nitrobenzene  are  now  manufactured  for  the  production  of 
aniline. 

Dinitro  and  tritritro  benzenes  are  also  known. 

Nitrotoluene , C6H4(N02)CH3.  This  substance,  which  corre- 
sponds in  general  with  nitrobenzene,  is  prepared  by  the  action  of 
fuming  nitric  acid  upon  toluene.  The  product,  which  gives  off 
an  odor  similar  to  bitter  almonds  (as  does  nitrobenzene),  may  be 
subjected  to  subsequent  purification.  It  also  produces  several 
toluidines  by  treatment  closely  corresponding  with  those  whereby 
nitrobenzene  is  reduced  to  aniline. 

Dinitro  and  trinitrotoluenes  are  also  known. 

Nitronaphthaleney  C10H7*NO2.  Several  nitronaphthalenes  are 
known  — mono-,  di-,  tri-,  tetra-,  according  to  the  conditions  of 
nitration.  They  may  be  produced  by  a properly  regulated  direct 
action  of  nitric  acid. 

They  are  generally  prepared  indirectly , for  example,  by  action 
of  nitric  acid  on  sulphonic  or  other  compounds  previously  obtained. 


Aromatic  Amines,  etc. 


When  aromatic  nitro  compounds  are  subjected  to  the  action  of 
nascent  hydrogen  they  undergo  a change  called  reduction.  This 
reduction  may  proceed  step  by  step : oxygen  being  gradually 
withdrawn  from  the  molecule,  and,  at  length,  hydrogen  added. 
The  important  series  of  compounds  thus  producible  may  be  illus- 
trated by  the  following  list  of  benzene  derivatives  due  to  such 
reduction  : 


Nitrobenzene  (two  molecules),  C6H5*N02 

c6h5-no2 


Azoxybenzene, 


C,6ti5*JN 


Azobenzene, 


Hydrazobenzene, 


Aniline  (two  molecules),  C6H5‘NH2 

C6H5-NH2 


i6o 


CARBON  COMPOUNDS. 


Phenylamine,  or  amidobenzene  (aniline),  C6H5NH2.  The  name 
aniline  is  derived  from  the  Spanish  word  anil  (one  form  of  a simi- 
lar oriental  word)  for  indigo.  This  name  was  assigned  because 
aniline  was  first  obtained  (by  Unverdorben  in  1826)  by  the  dry 
distillation  of  indigo.  The  compound  was  subsequently  dis- 
covered in  coal-tar.  Aniline  is  one  of  the  most  important  sub- 
stances employed  in  the  manufacture  of  colors.  Consequently,  it 
is  now  manufactured  on  a large  scale.  It  is  produced  by  some 
convenient  reducing  process  applied  to  nitrobenzene.  Several 
reduction  processes  have  been  employed,  for  example,  such  com- 
binations as  zinc  and  hydrochloric  acid,  iron  filings  and  acetic  acid, 
iron  filings  and  hydrochloric  acid,  have  been  used.  The  effect  of 
all  these  processes  is  the  liberation  of  nascent  hydrogen,  a part 
of  which  withdraws  oxygen  from  the  nitrobenzene,  and  a part  of 
which  takes  the  place  of  this  oxygen. 

On  the  large  scale,  aniline  may  be  produced  by  use  of  a large  iron  tank  pro- 
vided with  a stirrer  and  with  suitable  openings.  The  hydrochloric  acid,  the  iron, 
and  the  nitrobenzene,  are  introduced;  the  stirrer  is  set  in  motion,  and  the  mass 
is  gently  heated.  Reaction  sets  in  promptly,  and  aniline  is  produced.  At  the 
same  time,  this  substance,  which  acts  like  a compound  ammonia,  combines 
with  some  of  the  hydrochloric  acid  to  produce  a chloride,  called  aniline  hydro- 
chloride, C6H7NHCI.  This  latter  substance  is  a solid  salt  which  is  consider- 
ably used  in  commerce  under  the  name  of  aniline  salt.  The  mass  in  the  iron 
tank  is  removed  and  decomposed  by  lime.  The  lime  withdraws  the  hydrochlo- 
ric acid ; and  the  aniline,  called  aniline  oil,  is  separated  from  the  mixture  by 
distillation. 

Aniline  as  it  appears  in  commerce  is  called  aniline  oil,  for  it  is 
a liquid.  It  possesses  a peculiar  and  somewhat  agreeable  odor. 
At  a temperature  slightly  below  zero  it  solidifies.  It  becomes 
brown  in  color  upon  exposure  to  light  and  air.  Its  general  chemi- 
cal action  corresponds  to  that  of  ammonia  gas.  It  maybe  readily 
detected  in  aqueous  solution  by  adding  a water  solution  of  sodium 
hypochlorite  (easily  prepared  from  sodium  carbonate  and  bleach- 
ing powder).  The  aniline  changes  to  a blue  substance  which 
colors  the  liquid.  If  no  coloration  appears,  an  addition  of  a few 
drops  of  dilute  ammonium  sulphide  may  develop  a red  color  which 
may  be  likewise  considered  the  test  for  aniline. 

Aniline  is  distinctly  poisonous,  serious  effects  having  followed 
the  inhalation  of  considerable  quantities  of  its  vapor. 

Aniline  forms  a large  number  of  salts  with  ordinary  acids.  It 


AROMATIC  DERIVATIVES. 


161 


also  manifests  its  relationships  to  ammonia  by  producing  a corre- 
sponding double  platinum  salt. 

Aniline  is  the  starting  point  for  the  production  of  a very  large 
number  of  derivatives.  In  many  of  them,  methyl,  ethyl,  or  both, 
or  other  radicles  in  addition,  replace  the  appropriate  number  of 
atoms  of  hydrogen  of  the  aniline. 

Amidotoluenes , or  toluidines , C6H4(CH3)NH2.  The  formula  at 
once  shows  that  as  in  the  case  of  other  amido  compounds,  several 
toluidines  are  possible.  They  are  produced  in  general  as  are 
anilines ; that  is,  by  the  reduction  of  nitrotoluenes. 

Naphthylamine , C10H7'NH2.  Many  such  amines  are  known. 
They  are  prepared  by  reduction  of  nitro-  compounds. 

Anthramine , C6H4 : (C2H2)  : C6H3NH2,  This  is  the  amido 
anthracene  corresponding  to  amidobenzene  (aniline). 

Azo-  and  diazo-  compounds.  A great  number  of  substances  of 
these  classes  are  known.  Many  of  them  are  directly  or  indirectly 
of  great  importance  in  the  production  of  the  artificial  organic 
colors  so  largely  used.  Their  characteristic  feature  is  the  posses- 
sion of  the  group  — N : N — . 

Examples  of  azo  compounds  are  : 

Azobenzene,  C6H5*N2,C6H5 

Benzeneazonaphthalene,  C6H5*N2,CioH7 
Azonaphthalene,  CioI^’lSyCioH? 

The  azo  compounds  are  produced  by  a variety  of  operations,  but 
in  general  by  the  action  of  mild  reducing  agents  on  the  appro- 
priate nitro  aromatic  compounds,  or  by  the  action  of  diazo  com- 
pounds on  appropriate  amines  and  phenols.  (Generally  the 
diazo  compounds  are  not  separately  formed,  but  are  produced  in 
presence  of  the  amines  or  phenols  — the  solutions  being  kept  cool 
by  ice  or  otherwise  during  the  operation.) 

Azo  compounds  are  called  primary,  secondary,  tertiary,  accord- 
ing as  they  contain  one,  two,  or  three  groups  of 

The  diazo  compounds  contain  the  group  — N : N — but  it  is 
usually  attached  to  only  one  hydrocarbon  radicle.  They  exist  only 
as  compounds  containing  radicles  such  as  hydrogen,  chlorine,  ami- 
dogen,  etc.  The  diazo  compounds  are  usually  formed  by  action  of 
nitrous  acid  or  of  some  compound  that  can  easily  generate  it, 
e.  g.  sodium  nitrite  and  a mild  acid,  upon  amido  compounds. 


n 


CARBON  COMPOUNDS. 


162 


When  nitrous  acid  acts  upon  ammonia  gas,  the  group  N2  is 
liberated  in  accordance  with  the  following  equation  : 


nh3  + hno2  = n2  + 2H20 


When,  however,  in  place  of  NH3,  the  corresponding  organic 
amido  compound  (a  compound  ammonia)  is  used,  instead  of  the 
nitrogen  being  liberated,  it  enters  as  a constituent  of  the  new 
prodiLct. 

Examples  of  diazo  compounds  are  : 

Diazobenzene  nitrate,  C6H5*N2*N03 


Diazophenol  nitrate, 
Diazobenzene  sulphonic  acid, 


Diazonaphthalene  sulphonic  acid, 


C6H4(OH)-N2N03 


SO; 


C6H4' 

xn2  / 

CioHc^S°s\ 

N2 


An  enormous  number  of  azo  coloring  compounds  are  now  pro- 
duced by  a diazotising  process  whereby  the  operation  goes  on  in 
presence  of  two  very  different  aromatic  compounds  (great  range 
being  practicable — various  phenols,  naphthols,  amines,  sulphonic 
acids,  acids,  etc.,  being  used). 


— N — 

Azines  contain  N2,  but  with  the  structure 

— N— 


Aromatic  Oxygen  Compounds. 


Quinone,  benzoquinone,  CeH402 


Naphthaquinone , CioHe02 


Anthraquinone , Ci4H802 


AROMATIC  DERIVATIVES . 


163 


Dioxyanthraquinone  (alizarin),  C14H804,  is  an  orange  colored 
substance  not  readily  soluble  in  water  or  dilute  acids.  It  dis- 
solves, however,  in  alkaline  liquids,  producing  a magnificent 
purple  color.  Alizarin  tends  to  combine  with  oxides  of  the 
metals  (with  calcium  oxide,  producing  calcium  alizarate  as  a 
purple  precipitate.)  • 

From  alizarin,  by  the  use  of  chemical  agents,  a large  number 
•of  derivatives,  many  of  them  colored,  have  been  produced. 

Alizarin  is  one  of  the  coloring  matters  obtained  from  the  mad- 
der root.  It  does  not  exist  ready  formed  in  the  root ; it  exists 
there  as  a glucoside  called  rubian,  which  produces  glucose  and 
alizarin  under  the  influence  either  of  a special  ferment  (also  in 
the  root)  or  of  dilute  acids.  The  madder  root  has  long  been 
used  in  India  and  many  parts  of  Europe  as  a dye  stuff. 

Two  German  chemists,  Graebe  and  Liebermann,  while  experi- 
menting upon  alizarin  from  madder,  discovered  that  it  could 
be  decomposed  so  as  to  yield  a hydrocarbon  called  anthracene, 
previously  recognized  as  existing  in  coal  tar.  Thereupon  they 
undertook  to  turn  anthracene  back  into  alizarin,  and  as  a result  of 
earnest  labor  and  a certain  amount  of  good  fortune  they  succeeded. 

First.  The  process  of  Graebe  and  Liebermann  for  making  alizarin  was  some- 
what as  follows : 

Starting  with  anthracene,  they  oxidized  it  into  anthraquinone.  Next  they 
turned  anthraquinone  into  dibromanthraquinone ; they  heated  this  substance 
with  potassium  hydroxide,  thus  forming  potassium  alizarate ; they  decom- 
posed the  potassium  alizarate  with  hydrochloric  acid,  and  thus  obtained  aliza. 
rin.  In  certain  of  their  operations,  where  several  isomers  were  possible,  they 
had  the  good  fortune  to  produce  the  particular  isomer  necessary.  It  has  since 
become  apparent  that  if  they  had  hit  any  one  of  several  other  isomers,  the  arti- 
ficial production  of  alizarin  might  have  been  long  delayed. 

Second.  Alizarin  is  at  present  produced  by  a process  which  dispenses  with 
bromine.  It  is,  in  brief,  as  follows  : 

Anthracene  is  oxidized,  by  use  of  sodium  dichromate  and  sulphuric  acid,  into 
anthraquinone;  anthraquinone  is  sulphonated,  by  fuming  sulphuric  acid  into 
anthraquinone  sulphonic  acid;  the  sulphonic  acid  is  fused  with  sodium  hydrox- 
ide under  pressure  in  a closed  vessel,  to  form  sodium  alizarate;  the  sodium 
alizarate  is  decomposed  by  hydrochloric  acid  to  form  alizarin. 


Phenyl  ether , C6H5OC6H5.  This  substance 
corresponds  in  type  of  structure  with  the  fatty 
ethers.  Although  rather  a stable  compound,  one 
radicle  in  it  may  be  replaced  by  an  alkyl  radicle, 
thus  giving  rise  to  a series  of  aromatic  mixed 
ethers.  (Compare  with  the  fatty  ethers,  p.  76) 


1 64 


CARBON  COMPOUNDS. 


Aromatic  Compounds  Containing  Hydroxyl. 

An  enormous  number  of  such  compounds  are  known.  The 
names  employed  are  various,  but  they  generally  have  the  syllable 
ol  (alcohol  designation)  at  the  end  of  some  part  of  the  name.  Of 
course  one  or  more  molecules  of  hydroxyl  may  be  attached  to  the 
nucleus ; moreover,  one  or  more  other  radicles  may  be  attached 
at  the  same  time.  Again,  when  an  aromatic  hydrocarbon  has 
side  chains  the  hydroxyl  may  be  attached  either  to  the  nucleus  or 
to  the  side  chain,  thus  affording  at  least  two  sets  of  compounds. 
Hydrosulphuryl,  HS,  accomplishes  a series  of  similar  substitu- 
tions. 


c6h5-oh 

c6h5-sh 

Phenol  (carbolic  acid) 

Phenyl  sulphydrate  (phenyl  mercaptan) 

c6h5-ch2oh 

C6H4(CH3)OH 

Benzyl  alcohol  (a  toluene  derivative) 
Cresol  (a  toluene  derivative) 

C6H4(OH)2 

4 4 

( Ortho ) catechol  (from  catechu) 

(Meta)  resorcinol 

(Para)  quinol  (hydroquinone) 

C6H3(OH)3 

1-2-4  Pyrogallol  (pyrogallic  acid) 

CioH7-OH 

Alpha  and  beta , naphthol 

c14h9-oh 

Anthrol 

Phenol , also  called  carbolic  acid,  C6H5*OH.  This  substance  is 
obtained  by  processes  of  distillation  and  washing,  and  sometimes 
by  crystallization,  from  coal-tar.  Phenol  may  be  produced, 
however,  by  a variety  of  chemical  processes.  Some  of  the 
phenol  furnished  in  trade  is  of  a very  high  degree  of  purity, 
appearing  as  white  crystals.  Other  specimens  contain 
certain  aromatic  compounds  which  lead  it  to  become  red- 
colored  and  to  deliquesce  when  exposed  to  the  air.  The 
pure  article,  however,  does  not  redden  under  the  influence  of 
light  and  air. 


H 

O 

A 


\ 


Phenol,  or  carbolic  acid,  is  largely  employed  as  a disinfectant 
or  germicide.  Sometimes  it  is  used  mixed  with  water  or  other 
materials  ; as  for  instance,  diffused  through  soap.  In  some  sur- 


AROMATIC  DERIVATIVES. 


165 


gical  operations,  a spray  of  the  aqueous  solution  is  employed,  with 
excellent  effect,  with  a view  to  the  prevention  of  the  growth  of 
microbes.  It  is  not  now  considered,  however,  as  efficient  an  anti- 
septic as  it  was  formerly  thought  to  be.  It  is  a very  violent 
poison,  when  taken  into  the  system  of  the  higher  animals? 
and  cases  of  poisoning  often  occur  when  it  is  accidentally  or 
intentionally  administered.  It  is  considerably  used  in  the  manu- 
facture of  salicylic  acid,  also  of  picric  acid,  aurin,  azo-colors,  etc. 

Phenol  was  formerly  regarded  as  an  acid  (carbolic  acid)  because 
it  forms  combinations  with  sodium,  potassium,  and  other  metals. 
These  compounds  are  still  called  carbolates  or  phenates.  It  has 
-also  been  viewed  as  an  alcohol,  because  it  contains  the  hydroxyl 
group  OH.  It  is  now,  however,  placed  in  a new  class — the 
phenols — of  which  itself  is  the  typical  compound. 


\/ 

N02 


q Picric  acid,  trinitrophenol , CeH2(N02)30H.  Picric  acid  is 

not  usually  manufactured  by  the  direct  action  of  any  acid  on 
N02r  1NO2  phenol.  Instead,  a sort  of  intermediate  product,  phenol-sul- 
phonic  acid  is  employed.  On  the  large  scale,  phenol  is  mixed 
with  sulphuric  acid  and  nitric  acid.  In  due  time,  crystals  of 
picric  acid  separate  from  the  mixture  as  brilliant  yellow  scales. 
They  are  subjected  to  subsequent  purification. 

Picric  acid  is  largely  used  in  the  arts.  Its  most  marked  characteristic,  after 
its  intensely  bitter  taste,  is  its  power  of  dyeing  animal  matters  yellow.  It  colors 
the  skin,  fibres  of  silk  or  of  wool,  portions  of  quill,  portions  of  leather.  It  does 
not,  however,  readily  color  cotton  and  other  vegetable  fibres.  Picric  acid  is 
exceedingly  poisonous.  Notwithstanding  this  fact  it  is  said  that  minute  quan- 
tities of  it  are  sometimes  used  in  beer  to  impart  bitterness. 

Picric  acid  is  used  to  some  extent  to  produce  picrates  for  employment  in  cer- 
tain kinds  of  gunpowder  and  similar  explosives. 


Pyrogallol , C6H3(OH)3,  (1-2-4).  This  substance,  commonly 
called  pyrogallic  acid,  is  produced  as  a sublimate  when  gallic  acid, 
C6H2(OH)3COOH,  is  heated.  Pyrogallol  has  to  a marked  degree 
the  power  of  absorbing  oxygen.  A solution  of  the  substance  in 
potassium  hydroxide  is  very  efficient  in  this  way.  Indeed  it  is 
often  used  in  gas  analysis  for  absorbing  oxygen  from  its  mixture 
with  other  gases. 

This  affinity  of  pyrogallol  for  oxygen  leads  it  also  to  reduce 
compounds  of  the  metals,  of  gold,  silver,  and  mercury,  for  example. 


CARBON  COMPOUNDS. 


1 66 


On  this  account  pyrogallol  is  considerably  used  in  photography  as 
a developer. 

The  oxidation  of  pyrogallol  and  its  compounds  generally  affords 
dark-colored  products. 

Cresol  C6H4(CH3)  *OH,  is  a hydroxyl  substitution  product  of 
toluene,  C6H5CH3,  just  as  phenol  is  a similar  product  of  benzene, 
C6H6.  Many  cresols  are  known. 

It  has  long  been  noticed  that  when  certain  substances,  such  as 
coal  and  wood,  are  distilled  for  the  production  of  gas,  certain  of 
the  oils  condensed  are  capable  of  coagulating  albumen  and  that 
they  prevent  putrefaction.  On  account,  then,  of  the  power  of 
preserving  meat,  the  name  creasote  has  been  applied  to  them. 
The  word  is  derived  from  two  Greek  words  ( xpia c,  kreas,  meat  * 
and  (Tcb^a) , sozo,  to  preserve).  Chemists  have  carefully  studied 
the  creasote  derived  from  the  distillation  of  wood  and  that  derived 
from  the  distillation  of  coal,  and  have  discovered  that  while  they 
have  a general  resemblance,  both  consisting  of  mixtures  of  water 
with  various  aromatic  compounds,  yet  they  have  important  differ- 
ences. It  is  now  known  that  the  creasote  of  wood  contains  cresol, 
or  cresyl  alcohol,  which  is  different  from  phenol,  but  has  a general 
correspondence  with  it. 

Naphthol , C10H7‘OH.  Members  of  the  a-  and  /?  series  are 
known.  They  are  prepared  in  general  by  fusing  the  proper  sul- 
phonic  acids  or  the  proper  sulphonates  with  caustic  soda  or 
potash. 

The  napthols  are  the  starting  points  of  an  immense  series  of 
products  which,  while  retaining  the  hydroxyl  group,  may  be  sul- 
phonated,  nitrated,  reduced  to  amides,  azotized,  diazotized,  etc. 

Anthrol , C„H4(C2H2)C6H3'OH.  This  substance  is  prepared  by 
fusing  anthracene  sulphonic  acid  with  potassium  hydroxide. 


Aromatic  Acids  : Carboxylic  and  Sulphonic  Acids. 

Carboxylic  acids.  The  aromatic  hydrocarbons  form  the  bases  of 
an  enormous  number  of  acids.  In  some  of  them,  one  or  more 
groups  of  carboxyl,  COOH,  exist.  This  radicle  may,  however,  be 
attached  either  to  the  ring  nucleus  or  to  the  side-chain  ; thus  its 
position  involves  two  sets  of  carboxylic  acids.  Of  course  such 
acids  form  salts  with  metals. 


AROMATIC  DERIVATIVES. 


1 67 


Carboxylic  Acids.  First  Series. 


mono 

benzoic  acid, 

C6H5*COOH 

di 

1-2  phthalic  acid, 

C6H4  (COOH) 

1-3  isophthalic  acid, 

< i 

1-4  terephthalic  acid, 

n 

Jiexa 

mellitic  acid, 

C6  (COOH)6 

Carboxylic  Acids.  Second  Series. 

Phenylformic  acid,  CeHg.COOH  (benzoic  acid) 

Phenylacetic  acid,  C6H5*CH2*COOH 

Phenylpropionic  acid,  C6H5*CH2*CH2*COOH  (hydrocinnamic  acid) 

Phenylacrylic  acid,  CeH^CH  : CH'COOH  (cinnamic  acid) 

Benzoic  acid , C6H5COOH.  This  substance  is  formed  by  the 
dry  distillation  of  gum  benzoin.  This  gum  is  obtained  as  the 
result  of  incisions  in  the  trunk  of  a tree  growing  in  oriental 
countries.  The  benzoic  acid  may  be  separated  from  the  gum  by 
distilling  the  latter  in  a suitable  vessel.  The  benzoic  acid  sub- 
limes in  the  form  of  delicate  white  crystalline  flakes.  Benzoic 
acid  is  now  manufactured  from  aromatic  compounds  and  may  be 
produced  synthetically.  Benzoic  acid  forms  a large  series  of 
salts  as  well  as  many  derivatives. 

Mellitic  acid , C6(COOH)6.  This  is  prepared  from  honeystone, 
a mineral  (containing  an  aluminium  salt  of  mellitic  acid)  occur- 
ring in  certain  seams  of  brown  coal. 

Salicylic  acid , C6H4(OH)COOH.  This  acid  occurs  in  certain 
plants  ( spircea ).  The  compound  methyl  salicylate  occurs  in  oil  of 
wintergreen  (derived  from  gaultheria).  The  acid  is  now  made  in 
large  quantity,  by  Kolbe’s  process,  from  phenol,  C6H5OH.  The 
phenol  mixed  with  caustic  soda  is  subjected,  under  special  condi- 
tions, to  carbon  dioxide  gas,  C02.  The  first  product,  which  is 
impure,  is  purified  by  crystallization,  etc. 

The  substance  forms  white  crystals.  It  produces  a series  of 
salts.  It  is  used  as  an  antiseptic.  (Its  power  appears  to  be  due 
to  the  fact  that  it  readily  decomposes  into  phenol  and  carbon 
dioxide.) 

Gallic  acid , C6H2(OH)3COOH.  This  acid  exists  in  nutgalls 
and  certain  other  astringent  vegetable  matters  (usually  mixed 
with  a variety  of  other  substances).  The  acid  may  be  extracted 
from  nutgalls  or  it  may  be  prepared  artificially. 

Gallic  acid  is  a white  crystalline  substance.  It  forms  a series 


1 68 


CARBON  COMPOUNDS. 


of  gallates.  With  ferric  salts  it  produces  black  precipitates 
(writing  inks)  which,  however,  easily  dissolve. 

Gallic  acid  by  heating  produces  pyrogallol  and  carbon  dioxide. 

Gallic  acid  does  not  precipitate  gelatine  solutions  as  tannic  acid 
does. 

Tannic  acid  or  tannin , C6H2(OH)3COO’C6H2(OH)2,COOH. 
The  term  tannin  has  been  applied  in  general  to  the  astringent 
substance  which  exists  in  a large  number  of  vegetable  products 
suitable  for  tanning  animal  skins  to  produce  leather.  Such 
products  are  nutgalls,  leaves  and  twigs  of  sumach,  oak  bark  and 
other  barks,  catechu,  gambier,  etc. 

In  solutions  of  gelatine,  tannic  acid  produces  an  insoluble  pre- 
cipitate, and  it  is  assumed  that  such  a precipitate,  more  or  less 
completely  formed  in  the  animal  hide,  performs  an  important  part 
of  the  operation  of  producing  leather. 

Of  late  an  entirely  new  method  of  tanning  has  been  successfully  introduced. 
By  it,  the  skins  are  soaked  first  in  a solution  of  potassium  dichromate  and 
hydrochloric  acid.  After  the  chromic  acid  has  saturated  the  skins,  they  are 
drained,  and  then  introduced  into  another  bath  containing  sodium  hyposul- 
phate.  As  a result,  a green  chromium  oxide  is  produced,  which  combines 
with  the  hide  fibre  to  produce  a very  stable  compound. 

Ink.  Tannic  and  gallic  acids  are  very  much  used  in  the  prepa- 
ration of  inks.  Indeed,  it  is  now  believed  that  for  permanency 
no  inks  surpass  those  containing  gallic  principles  and  iron.  The 
advantage  consists  in  the  fact  that  the  iron  compounds  remain 
for  a long  time  in  the  paper ; and  even  if  the  coloring  matter  is 
faded,  the  application  of  some  substance,  like  potassium  ferro- 
cyanide,  will  make  the  faded  writing  legible ; the  reason  is  found, 
of  course,  in  the  fact  that  the  iron  then  produces  Prussian  blue. 

In  the  manufacture  of  ordinary  black  ink,  crushed  nut  galls,  ferrous  sulphate, 
gum  arabic,  and  water,  are  employed.  The  galls  and  the  iron  produce  a very 
finely  divided  precipitate  having  a black  or  blue-black  color.  The  gum  arabic 
thickens  the  liquid  slightly,  and  so  prevents  the  subsidence  of  the  precipitate. 
In  order  to  avoid  mould,  a great  many  substances  have  been  recommended  as 
additions.  Oil  of  cloves,  salicylic  acid,  mercuric  chloride,  are  examples. 
Instead  of  nut  galls,  certain  cheaper  dyeing  materials,  such  as  logwood  extracts, 
are  often  employed  in  inferior  inks.  Sometimes  indigo  solutions,  or  other 
soluble  coloring  matters,  are  employed.  Thus,  in  many  cases  at  the  present 
day,  coal  tar  coloring  matters  are  used.  Printers’  ink  derives  its  color  from 
lamp  black.  India  ink  is  made  from  the  same  material. 

Indelible  ink  is  usually  an  ammoniacal  solution  of  silver  salts,  colored 


AROMATIC  DERIVATIVES. 


169 


slightly  with  indigo.  The  silver  compound  is  decomposed  by  the  organic 
matter  of  the  cloth  ; and  there  is  produced  either  metallic  silver,  black  by  reason 
of  its  fine  state  of  division,  or  else  some  black  compounds  of  silver. 

The  Sulphonic  Acids. 

Sulphuric  acid  applied  directly  or  indirectly,  under  varying 
conditions,  forms  sulphonic  acids,  with  not  only  hydrocarbons, 
but  also  with  a multitude  of  their  substituted  derivatives.  In 
all  these  acids  the  characteristic  feature  is  the  sulphonic  group, 
S03H,  of  which  one  or  more  molecules  may  be  present  in  a 
given  case.  The  hydrogen  of  this  group  is  replaceable  by  a 
metallic  element,  thus  forming  salts — the  sulphonates.  These 
sulphonic  acids  and  sulphonates  are  largely  used  as  intermediate 
compounds  in  progressing  from  a certain  compound  in  hand,  to 
one  whose  formation  is  desired. 

Benzene  sulphonic  acid , C6H5'S03H.  This  substance  is  pro- 
duced in  a variety  of  ways,  the  simplest  being  by  the  direct  action 
of  sulphuric  acid  on  benzene.  The  compound  is  a deliquescent 
solid.  It  forms  a variety  of  compounds  — with  metals  and  with 
other  hydrocarbon  radicles. 

Three  disulphonic  acids  are  known,  o,  m,  and  p.  These  also 
produce  an  immense  number  of  derivatives. 

The  other  hydrocarbons  of  the  benzene  series  also  produce  sul- 
phonic acids  and  derivatives. 

Naphthalene  sulphonic  acid , QoHySCbH.  This  substance  is 
prepared  by  direct  action  of  sulphuric  acid  on  naphthalene ; 
a-  and  /3-  forms  are  known.  Many  other  sulphonic  acids  of  naph- 
thalene are  known. 

Anthracene  sulphonic  acid , Ci4H9‘S03H.  Many  such  sulphonic 
acids  are  known. 

The  sulphonic  acids  already  mentioned  represent  some  of  the 
simplest  products  of  the  style  of  combination  under  discussion. 
Other  acids  formed  from  aromatic  nitro,  amido,  hydroxyl,  and 
other  substitution  compounds  — or  from  compounds  in  which 
several  different  radicles  enter  at  once  — are  known,  and  they  are 
of  great  importance  in  the  artificial  organic  color  industry. 

CO 

Saccharine , anhydro-sulphamido-benzoic  acid , \NH. 


CARBON  COMPOUNDS. 


170 


This  substance  is  a solid,  soluble  in  water,  and  about  five  hundred  times  as 
sweet  as  cane  sugar.  In  general  it  is  produced  as  follows  : toluene  is  changed 
into  toluene  sulphonic  acid;  then  this  is  oxidized  into  sulphobenzoic  acid; 
then  this  is  chlorinated  into  sulphobenzoic  acid  dichloride;  then  this  by  action 
of  ammonium  carbonate  is  changed  into  sulphamidobenzoic  acid;  then  this  by 
mild  acid  treatment  forms  the  saccharine.  (The  latter  trivial  name  is  an 
unfortunate  one,  but  it  is  in  use.) 

Saccharine  is  used  somewhat  in  medicine,  and  for  the  sweetening  of  foods  for 
patients  who  are  not  allowed  to  take  cane  sugar.  It  is  not  itself  in  any  sense  a 
food,  for  it  has  been  found  to  pass  through  the  animal  organism  unchanged. 

Artificial  Organic  Coloring  Matters. 

This  title  is  intended  to  be  more  comprehensive  than  the  term 
aniline  colors  (chiefly  aniline  derivatives) ; more  even  than  coal-tar 
colors.  This  latter  term  is  a convenient  and  appropriate  one,  for 
the  chief  raw  materials  for  the  artificial  organic  colors  come  from 
coal-tar. 

In  1826  Unverdorben  produced  aniline  by  the  destructive  distil- 
lation of  indigo.  Soon  after,  the  substance  was  detected  in  coal-tar, 
ready  formed.  It  is  now  made  in  enormous  quantities  indirectly 
(that  is  from  benzene)  from  coal-tar.  In  1835  Runge  observed  that 
a beautiful  violet-blue  color  is  produced  when  bleaching  powder  acts 
on  aniline.  In  1856,  W.  H.  Perkin  isolated  a magnificent  color, 
which  he  called  mauve,  which  he  had  produced  by  this  general  class 
of  reactions.  Later  A.  W.  Hofmann  and  many  others  studied 
the  constitution  of  this  class  of  colors,  the  conditions  under 
which  they  are  formed,  and  the  various  methods  of  production  ; 
these  researches  led  to  the  development  of  the  aniline  color  man- 
ufacture, and  they  laid  the  foundations  for  the  important  organic 
color  industries  of  the  present  day.  In  1868,  Graebe  and  Lieber- 
mann  produced  artificial  alizarine  from  anthracene  of  coal-tar, 
(and  later  W.  H.  Perkin  made  valuable  improvements  in  the 
process  employed.)  This  most  important  synthesis  has  been  fol- 
lowed by  the  production  of  a magnificent  series  of  alizarine  deriv- 
atives. These  noteworthy  achievements  have  been  followed  by 
the  production,  in  rapid  succession,  of  new  aromatic  colors,  bewil- 
dering in  number  and  complexity.  To-day  there  are  several  very 
large  color  factories  (employing  large  corps  of  chemists,  of  the 
highest  degree  of  skill),  and  manufacturing  daily  new  and,  if  pos- 
sible, yet  more  useful  products.  It  is  worthy  of  remark  that 
the  industrial  production  of  colors  on  a large  scale  has  advanced 


AROMATIC  DERIVATIVES. 


171 


the  theoretical  chemistry  of  this  department,  far  more  than  mere 
laboratory  experiments  could  possibly  have  done. 

The  following  important  general  principles  as  to  organic  coloring  compounds 
have  been  formulated  : 

1.  Practically  all  the  natural  as  well  as  artificial  organic  colored  bodies  are 
benzene  derivatives. 

2.  The  aromatic  hydrocarbons  are  colorless. 

3.  Hydrocarbon  derivatives  in  which  one  atom  of  hydrogen  is  replaced  by 
hydroxyl,  HO,  the  nitro  group,  NO2,  the  amido  group  NH2,  are  colorless.  The 
same  is  true  when  two  replacing  groups  just  alike  are  present. 

Thus  phenol,  C6H5OH,  nitrobenzene,  C6H5N02,  aniline,  C6H5-NH2,  are  col- 
orless. 

4.  Mixed  di-derivations  of  the  classes  mentioned  are  sometimes  colored, 
sometimes  not. 

Thus  trinitrophenol  (picric  acid)  CeH2(OH) (N02)3,  is  yellow;  nitraniline, 
C6H4(NH2)N02,  is  yellow. 

5.  Color  appears  to  be  dependent  upon  certain  molecular  groups  and  arrange- 
ments. Groups  of  this  character  are  called  chromophors.  Among  the  most 
important  chromophors  are : 


1 

0 

1 

0 

1 

• in  quinones, 

— N : N — 

in  azo  compounds. 

— N02  in 

nitro  compounds, 

1 

A methane  substitution  group  existing  in 

Q 

I 

mauve,  fuchsine,  (magenta,  solferino,)  and 

(R) 

similar  compounds  of  the  triphenylmethane 

— NH 

series. 

1 

— C— 

1 

Existing  in  the  aurins. 

(R) 

— 0 

0 

c 

/ \ 

= (R)  (R)  = Existing  in  alizarins. 

\ / 

C 

o 

6.  In  all  these  cases,  the  chromophors,  when  linking  aromatic  groups  of  the 
most  varied  kinds  produce  chromogenes.  These  chromogenes  are  not  dyes : 
they  become  dyes  on  the  substitution,  in  the  aromatic  radicles,  of  certain  special 
groups  like  OH  and  NH2. 

Thus  — N : N — is  a chromophor 

Azo  benzene  (yellow)  CeHs’NyCcHs  “ chromogene 

Amidoazobenzene  (yellow)  CeH5,N2,C6H4'NH2  “ dye 


CARBON  COMPOUNDS. 


172 


(The  hydrochloride  of  amidoazobenzene  was  formerly  sold  under  the  names 
aniline  yellow,  spirit  yellow.  It  is  not  now  used  except  as  a starting  point  for 
more  complex  and  more  serviceable  colors) 

7*  Generally  the  salts  of  dyes  have  stronger  colors  than  the  dyes  themselves  : 
thus  the  acid  dyes  give  stronger  colors  when  united  with  metallic  radicles — and 
the  basic  dyes  when  united  with  acid  radicles : 

Sodium  picrate  is  more  intensely  yellow  than  picric  acid;  the  salts  of  the 
base,  rosaniline,  are  more  deeply  colored  than  the  hydrate  of  that  base. 

8.  Increase  of  number  of  salt  forming  groups,  increases  depth  of  color  : 

Amidoazobenzene  Ci2H9N2(NH2)  is  yellow 

Diamidoazobenzene  Ci2H8N2(NH2)2  is  orange 

Triamidoazobenzene  Ci2H7N2(NH2)3  is  brown 


9.  When  the  hydrogen  of  amidogen,  NH2,  is  replaced  by  hydrocarbon  radicles 
the  color  often  advances  in  shade  in  a particular  direction  : thus  corresponding 
salts 


of  Rosaniline 
of  Phenylrosaniline 
of  Diphenylrosaniline 
of  Triphenylrosaniline 


C2oH19N3  are  red 

C2oHi8(C6H5)N3  are  red-violet 
C2oHi7(C6H5)2N3  are  blue-violet 
C20Hi6(C6H5)sN3  are  blue 


A recent  list  by  Schultz  and  Julius  names  and  describes  392 
such  colors,  now  or  recently  manufactured.  (This  number  in- 
cludes, of  course,  colors  capable  of  practical  use  in  the  arts  ; prob- 
ably many  thousands  of  colored  compounds  of  the  aromatic 
series  may  be  made  by  methods  now  understood,  but  certain  prin- 
ciples are  now  recognized  which  indicate  beforehand  that  most  of 
them  are  commercially  useless.)* 

The  coal-tar  colors  are  classified  by  the  dyer  and  colorist 
according  to  technical  standards,  that  is,  according  to  their  solu- 
bility or  insolubility  in  water  or  alcohol,  according  to  their  appli- 
cability to  cotton  or  to  wool  or  to  silk,  and  otherwise.  The 
chemist  prefers  to  classify  them  according  to  their  plan  of  struc- 
ture and  according  to  their  chemical  relationships. 

Schultz  and  Julius  arrange  artificial  organic  dyes  in  groups  as  follows  : 


I. 

Kitro-compounds, 

15  mentioned. 

2. 

Azoxy  “ 

3 

3- 

Hyd  razone-compou  nds , 

1 

4- 

Azo  “ 

212  “ 

5- 

Nitroso  “ 

5 

6. 

Oxyketone  “ 

23 

* Schultz,  G.  and  Julius,  P.;  Tabellarische  Uebersicht  der  Kiinstlichen  organischen  Farbstoffe 
Berlin,  1891.  It  contains  dates  of  the  discovery  of  individual  colors,  patents,  etc. 


AROMATIC  DERIVATIVES. 


1 73 


7- 

Diphenylmethane  compounds, 

3 

mentioned, 

8. 

Triphenylmethane  “ 

75 

“ 

9- 

Indophenol  “ 

2 

i i 

10. 

Oxazine  and  Thiazine  “ 

12 

< C 

11. 

Azine  “ 

18 

12. 

Artificial  indigo  “ 

3 

t ( 

13* 

Quinoline  “ 

7 

14. 

Acridine  “ 

4 

J5- 

Thiobenzyl  “ 

3 

i i 

16. 

Of  unknown  constitution, 

6 

< < 

392 

The  nitro  compounds . These  tend  to  produce  yellow  and 
orange  dyes. 

Picric  acid,  which  is  trinitrophenol,  is  a good  illustration.  Bril- 
liant yellow  is  a sodium  salt  of  dinitro  a-  naphthol-monosulphonic 
acid, 

H 

O 


The  azo  compounds . The  number  of  these  mentioned  shows 
their  relative  importance.  They  produce  nearly  all  colors  — 
many  yellows,  oranges,  and  browns,  reds,  greens,  blues,  and  even 
blue-blacks.  The  most  varied  aromatic  hydroxyl,  and  amido,  and 
sulphonic  compounds,  especially  of  the  naphthalene  series,  are 
diazotized  and  combined  to  produce  the  azo  dyes.  (See  p.  161.) 

Rosazurin  (Bayer)  which  dyes  cotton  a bluish-red  is  an  azo- 
compound, viz.  : 

Sodium  sulphonate  of  methyl-/9-naphthylamine-azo-ortho-tolu- 
ene-toluene-azo-methyl-/3-naphthylamine  sodium  sulphonate  : 


The  oxyketone  compounds.  These  include  chiefly,  the  alizarin 
compounds  and  other  anthracene  derivatives.  (See  p.  163.) 

The  triphenylmethane  compounds.  As  the  name  suggests,  the 


174 


CARBON  COMPOUNDS. 


structure  of  the  fundamental  molecule  of  such  compounds  is 
methane  (marsh  gas)  CH4,  in  which  three  atoms  of  hydrogen  are 
replaced  by  three  molecules  of  phenyl,  C6H5. 


C6h6 


C6h5 

Triphenyl  methane 


But  in  the  coloring  compounds  of  this  group  there  is  first , an 
amidogen  replacement  on  the  phenyl  ring,  second , a hydrocarbon 
replacement  in  one  or  more  of  these  amidogens  (see  p.  172), 
third,  a special  linkage  in  the  chromophor  (see  p.  171),  fourth,  an 
acid  radicle  combining  with  the  whole  base  formed  by  the  substi- 
tutions first  described. 

Thus  parafuchsine  is  C16H18N3C1. 


NH. 


Ordinary  fuchsine  (called  magenta, 
solferino,  and  by  other  names,)  has  the 
formula,  C2oH19N3,HC1,  as  shown  in  the 
diagram  below  : 


X \ 
\ X 


nh2 


nh3 


NH 

Cl 

Parafuchsine 


./  \ 

x_x 


NH; 


In  ordinary  fuchsine  the  presence  of 
CH3  on  one  of  the  rings  shows  that 
the  compound  is  a toluidine  derivative 
as  well  as  an  aniline  derivative.  Thus 
it  cannot  be  made  from  benzene  alone : 
toluene  is  necessary  in  addition. 


ch3 


— nh2 
Cl 


Ordinary  fuchsine 
(Rosaniline  hy- 
drochloride) 


AROMATIC  DERIVATIVES. 


75 


nh2 


— nh2oh 

True  base  of 
fuchsine 


The  true  base  of  fuchsine  is  supposed 
to  have  the  formula  C2oH2oN3‘OH,  with 
the  structure  shown  in  the  margin  : it 
is  supposed  that  this  base  changes, 
immediately  after  formation,  to  the 
rosaniline  base , having  the  same  literal 
formula,  but  having  the  hydroxyl  in  a 
slightly  different  position. 


The  term  rosaniline  is  often  used  somewhat  ambiguously.  The  relations  of 
a few  of  the  different  important  compounds  which  this  name  involves  may  be 
stated  as  follows  in  comparison  with  ammonia  compounds  : 

Parent  substance : ammonia  gas,  NH3  ; rosaniline,  C20Hi9N3 

True  base : ammonium  hy-  rosaniline 

droxide,  NH4OH ; base,  C20H20N3OH 

Chlorine  salt : ammonium  rosaniline  chlo- 

chloride,  NH4CI;  ride  (fuchsine),  C20H20N3C1 


The  tetraphenylmethane  compounds  are  produced  from  a vari- 
ety of  substances,  but  largely  from  substitution  products  of  the 
benzene  series. 

The  colors  produced  are  reds,  blues,  and  violets,  of  magnificent 
shades — but  yellows  and  greens  are  also  produced. 


Phenolphthalein, 


C6H4OH 

/ 

— C— QH4OH  belongs  to  this  group. 

n 

c6h4co 

o 


Its  weak  alcoholic  solution  is  colorless ; upon  addition  of  a 
minute  quantity  of  an  alkali  a beautiful  red  color  is  developed. 
The  substance  is  useless  as  a dye  ; it  is  only  used  as  an  indicator 
in  the  laboratory. 

Substances  of  unknown  constitution.  Among  these  is  the  im- 


176 


CARBON  COMPOUNDS. 


portant  aniline  black.  It  is  supposed  to  differ  in  composition 
according  to  the  details  of  the  process  of  its  production.  It  is 
thought  to  be  some  kind  of  salt  (often  a chromium  compound)  of 
the  compound  nigraniline,  whose  formula  is  taken  temporarily  as 

(C,h,n)s. 

It  affords  the  fastest  and  deepest  black  shades  now  known. 
Its  production  depends  upon  the  following  general  principle  ; 
namely,  when  aniline  salt  is  mixed  with  a chlorate,  say  potassium 
chlorate,  in  presence  of  some  salt  of  a heavy  metal,  commonly  of 
copper  or  of  chromium  but  better  of  vanadium,  a dark  green  color 
is  produced,  which  becomes  black  under  the  influence  of  a mild 
alkali. 

This  color  is  largely  used  upon  cotton  in  calico  printing.  In  practice,  a paste 
is  made  containing  aniline  chloride,  sodium  chlorate,  a very  minute  amount  of 
ammonium  vanadate,  and  starch.  This  is  printed  upon  cloth  accox'ding  to  the 
pattern  desired.  The  cloth  is  then  dried  and  allowed  to  stand  for  some  time, 
when  it  is  subjected  to  ammonia  gas,  to  soap,  or  some  other  mildly  alkaline 
substance.  The  color  then  develops  as  a deep  and  permanent  black,  one  that  is 
not  easily  injured  by  the  sunlight,  by  air  or  moisture,  or  even  by  chemical 
agents. 


CHAPTER  XXIII. 


CERTAIN  NATURAL  ORGANIC  COLORING 
MATTERS,  etc. 

Indigotin , C16H10N2O2.  This  is  the  most  important  one  of  the 
many  coloring  matters  existing  in  indigo.  Indigo  is  largely  pro- 
duced from  the  leaves  or  stems,  or  both,  of  a small  shrub, 
indigofera  tinctoria ; but  several  other  plants  yield  it.  Indigo 
comes  chiefly  from  India,  but  it  is  also  produced  in  China,  Egypt 
and  Central  America.  In  India  the  plant  is  packed  in  large  vats 
and  soaked  in  water  ; fermentation  sets  in;  the  liquid  is  drawn  off 
into  other  vats  in  which  it  is  violently  agitated  with  paddles,  by 
which  the  oxygen  of  the  air  is  introduced ; finally  the  liquid  is 
allowed  to  rest,  whereupon  the  blue  coloring  matter  subsides. 
The  pasty  matter  is  filtered,  and  the  solid  part  is  pressed  into 
small  cubes. 

Indigo  of  commerce  contains  a variety  of  compounds  : Indigo- 
gluten indigo-brown , indigo-red , and  a glucoside  indican.  When 
indican  is  treated  with  certain  acids  it  yields  indirubin  and  indi- 
gotin , C16H10N2O2,  the  latter  the  most  important  coloring  matter 
of  indigo. 

Indigotin  may  be  sublimed  as  a purple  vapor,  by  gently  heating 
indigo.  It  may  be  prepared  from  indigo-white  also. 

Indigo-white , C16H12N202,  is  produced  when  indigo  is  subjected 
to  mild  reducing  agents,  in  presence  of  free  alkali. 

Fritsche’s  method  illustrates  its  production  ; place  in  a flask  : 

5 gms.  finely  powdered  indigo, 
io  gms,  grape  sugar, 

50  c.c.  of  a 40%  solution  of  sodium  hydroxide, 

150  c.c.  water, 

300  c.c.  90 °fo  alcohol; 


12 


(i77) 


78 


CARBON  COMPOUNDS. 


heat  the  mixture  in  a water  bath  for  30  minutes  ; allow  the  whole 
to  subside.  The  clear  liquid  should  now  contain  white  indigo. 
Draw  off  the  clear  liquid  by  means  of  a siphon  into  a beaker. 
Pass  into  it  first  a strong  current  of  carbon  dioxide,  then  a current 
of  air;  indigotin  should  now  be  precipitated. 

Under  the  influence  of  concentrated  sulphuric  acid  indigotin 
forms  two  sulphonic  acids — mono-  and  di-. 

Indigotin  monosulphonic  acid,  C10H9(HSO3)N2O2,  is  insoluble  in 
dilute  acids,  but  soluble  in  water.  Its  sodium  salt  is  called  indigo- 
purple. 

Indigotin  disulphonic  acid , C10H8(HSO3)2N2O2,  was  formerly 
called  sulphindigotic  acid.  It  quickly  forms  under  action  of  sul- 
phuric acid.  When  its  dilute  solution  in  water  is  precipitated  by 
common  salt  a paste  called  indigo-extract  is  formed.  The  sodium 
salt  is  called  indigo-carmine. 

Indigotin  is  converted  by  oxidizing  agents  into  isatin , C8H5NO. 

Indigotin  has  been  produced  by  an  artificial  synthesis  (Baeyer). 

Alizarin,  C14H804.  This  substance  has  already  been  referred 
to  as  the  chief  coloring  matter  obtained  from  madder,  the  ground 
root  of  rubia  tinctorum.  Madder  has  long  been  grown  in  Asia 
Minor,  and  later  in  various  parts  of  Europe — Italy,  France,  Hol- 
land, Russia.  For  ages  it  has  been  the  chief  dyestuff  used  in  the 
manufacture  of  calico  and  turkey  red  in  the  Orient,  and  up  to  the 
time  of  the  production  of  artificial  alizarin,  for  the  same  purpose 
in  Europe  and  the  United  States.  It  has  been  most  carefully 
studied,  and  it  has  been  found  to  contain  a great  many  coloring 
matters.  The  chief  ones  are  alizarin,  C14H804,  and  purpurin, 
C14H805.  On  calicoes,  with  different  mordants,  madder  is  able  to 
produce  blacks,  various  shades  of  violet,  chocolate,  red  and  pink ; 
and  the  colors  are  very  fast. 

Moritannic  acid,  C15H1207(?).  This  is  one  of  the  coloring  mat- 
ters obtained  from  the  substance  known  as  fustic  or  old  fustic,  the 
wood  of  moms  tinctoria.  But  the  wood  contains  other  coloring 
substances  in  addition. 

Fustic  is  essentially  a yellow  wood.  It  is  used,  with  mordants 
containing  tin  or  aluminium,  to  produce  yellow  colors.  When 
mixed  with  other  woods,  and  with  mordants  containing  iron  or 
chromium,  it  is  used  to  produce  shades  of  brown,  olive,  etc. 


ORGANIC  COLORING  MATTERS,  ETC. 


179 


Hccmatoxylin , C1hH1406,  etc.  This  substance  is  the  principal 
coloring  matter  obtained  from  logwood,  the  wood  of  hcematoxylon 
campechianum. 

This  important  dyewood  comes  from  the  West  Indies.  It 
appears  to  contain  glucosides,  which  decompose,  under  proper 
treatment,  into  glucose  and  the  true  dyeing  compounds  haematox- 
ylin,  C16H1406,  (a  white  substance,  which  forms  colored  compounds 
by  combining  with  metallic  oxides)  and  haematein,  C16H1206  (a 
reddish  brown  substance  produced  by  oxidation  of  haematoxylin). 

Logwood  is  very  largely  used  for  blacks  and  greys  on  all  sorts 
of  fabrics,  principally  by  use  of  mordants  containing  iron  or  chro- 
mium or  aluminium. 

Brazilin , C22H1807.  This  substance  is  obtained  from  Brazil- 
wood, a member  of  the  casalpina  family  and  one  of  a group  of 
woods — peach  wood,  lima  wood,  sapan  wood,  Pernambuco  wood — 
which  are  closely  allied.  They  appear  to  contain  glucosides, 
which  yield  brazilin.  Brazilin  oxidizes  in  the  air,  producing  bra- 
zilein,  C22H1607.  The  woods  referred  to  were  much  used  formerly 
to  produce  shades  of  red  and  pink. 

Santalin , C15H1405.  This  substance  appears  to  be  obtainable 
from  several  varieties  of  hard  red  woods — red  sanders,  barwood 
and  camwood.  They  were  much  used  formerly  for  producing  reds 
and  composite  colors,  such  as  brown,  etc. 

Quercitrin , C21H22012.  This  is  the  principal  coloring  substance 
derived  from  quercitron  bark , the  bark  of  a species  of  quercus. 
The  coloring  principles  are  quercitrin,  C21H22012,  and  quercetin, 
C24H16Oio,  both  yellow  substances,  which  dissolve  in  alkalies. 
From  quercitron,  a yellow,  powdered  extract  called  flavine  is  pro- 
duced. It  is  used  for  producing  yellows. 

Carminic  acid , C17H18O10.  This  is  the  principal  coloring  com- 
pound in  the  commercial  substance  known  as  cochineal,  a mate- 
rial consisting  of  the  dried  and  shrivelled  bodies  of  the  female  of 
an  insect  coccus  cacti , which  lives  on  a variety  of  cactus.  The 
plant  and  insect  (natives  of  Mexico  and  Guatemala)  have  been 
introduced  into  the  Canary  Islands,  Algeria,  Java  and  Australia. 
About  70,000  individual  insects  are  required  to  make  one  pound 
of  cochineal. 

Carminic  acid  is  a purple  solid  soluble  in  water,  alcohol,  and 


i8o 


CARBON  COMPOUNDS. 


other  solvents.  It  dissolves  in  caustic  alkalies,  producing  a splen- 
did purple  color.  It  adheres  to  certain  mineral  substances,  like 
aluminic  hydroxide,  A1206H6,  when  they  are  precipitating,  forming 
lakes. 

It  is  largely  used  for  dyeing  fast  scarlets  and  crimsons  on 
woolen  goods,  tin  mordants  being  used. 

Alkaloids. 

1.  The  name  alkaloid  is  applied  to  members  of  a certain  class 
of  substances  (about  175  are  known)  whose  representatives  are 
found  in  plants  or  natural  plant  products. 

2.  In  some  cases  a given  plant  contains  more  than  one  alka- 
loid. Thus  in  Peruvian  bark  23  different,  but  closely  related, 
alkaloids  have  been  detected.  In  opium,  from  the  poppy,  as  many 
as  1 7 have  been  reported. 

3.  The  alkaloids  contain  nitrogen  in  addition  to  carbon,  hydro- 
gen, and  oxygen  (although  three  are  known  which  do  not  contain 
oxygen). 

4.  They  are  all  compounds  of  an  aromatic  type,  that  is,  their 
molecules  have  a ring  structure.  But  they  appear  to  have  close 
relations  to  the  substance  called  pyridine,  and  they  are  often 
spoken  of  as  pyridine  compounds. 

Pyridine , C6H5N,  is  a poisonous,  colorless  liquid  found  in 
coal-tar,  in  the  oil  distilled  from  bones  (bone-oil,  Dippel’s  ani- 
mal oil,)  and  elsewhere.  Its  molecule  has  the  structure  repre- 
sented by  the  adjacent  diagram  : a benzene  ring  in  which  one 
atom  of  carbon  has  been  replaced  by  an  atom  of  nitrogen. 
Pyridine  bears  a certain  resemblance  to  ammonia  gas  : it  fumes 
with  hydrochloric  acid,  uniting  with  it  to  form  a chloride  (or 
hydrochloride)  : it  precipitates  many  metals,  as  hydroxides, 
from  their  solutions  : it  makes  a deep-blue  solution  with  copper 
salts,  etc. 

5.  The  alkaloids  act  like  ammonia  gas  in  certain  ways:  they 
unite  directly  with  hydrochloric  acid  (and  other  acids)  without 
evolution  of  hydrogen,  forming  a salt  or  salts 

6.  The  alkaloids  and  their  salts  when  administered  to  living 
animals  produce  powerful  effects : stimulating,  or  narcotic,  or 
poisonous,  or  remedial,  according  to  the  conditions  of  their 
administration.  (Hence  the  portions  of  the  plants,  containing 
alkaloids,  manifest  these  properties,  in  a modified  degree,  it 
may  be.) 


H 

C 

/ ^ 

HC  CH 

II  I 

HC  CH 

\ ^ 

N 

Pyridine, 

C6H5N 


ALKALOIDS. 


1 8 1 


The  following  is  a list  of  a few  of  the  more  important  alkaloids  : 

1.  Alkaloids  Without  Oxygen. 

Coniine , C8H17N.  It  exists  in  poisonous  hemlock,  coninm 
maculatum. 

Nicotine , C10H14N2.  It  occurs  in  the  leaves  of  tobacco,  and 
elsewhere.  It  is  ordinarily  a liquid,  very  volatile,  highly  poison- 
ous. Tobacco  appears  to  contain  nicotine  in  very  varying  quanti- 
ties. The  amount  varies  from  1.5  % to  nearly  8 %. 

Sparteine , C15H26N2.  It  occurs  in  the  common  broom,  spartium 
scoparium. 

Curarine , C18H35N  ( ? ).  It  occurs  in  a resinous  poison  used  on 
arrow  heads  by  South  American  aborigines. 

II.  Alkaloids  Containing  Oxygen. 

Caffeine  or  theine>  C8H10N4O2.  It  occurs  in  certain  vegetables, 


as  follows  : 

Coffee, 1.  to  1.3  % 

Tea, 2.  to  4.  % 

Guarana,  about  ....  5.  % 

Mate,  about 1.5  % 

Kola  seeds  (when  dried),  about  . 2.  % 

Cocoa,  a small  amount. 


Several  methods  of  extraction  have  been  devised.  In  general 
a strong  water  extract  is  first  made;  then  slaked  lime  is  added  to 
free  the  alkaloid  ; next,  the  alkaloid  is  dissolved  in  chloroform  or 
some  similar  solvent ; upon  evaporating  the  solvent  the  alkaloid 
is  obtained. 

Sweepings  from  the  tea-warehouses  of  London  constitute  the 
raw  material. 

Theobi'omine , C7H8N402.  It  exists  in  small  quantity  in  the  seeds 
from  which  chocolate  is  prepared. 

The  word  cocoa  is  somewhat  ambiguous. 

The  chocolate  tree  (Theobroma  Cacao)  produces  those  seeds  which,  ground 
and  otherwise  prepared,  afford  the  preparations  known  as  chocolate  and  cocoa. 
They  also  afford  an  oil  called  cacao  butter  (cacao  pronounced  ka-ka'o). 

The  cocoanut  palm  (Cocos  Nucifera)  produces  the  fruit  called  cocoanut.  The 
wood  of  the  tree,  the  fibre,  the  juice  and  flesh  of  the  cocoanut  and  its  shell,  are 
most  useful  products. 


CARBON  COMPOUNDS. 


•182 


The  coca  shrub  (Erythroxylon  Coca)  produces  a leaf  which,  when  dried,  is  an 
important  drug.  The  shrub  grows  in  South  America,  and  is  largely  used  by 
the  inhabitants  as  a stimulant.  The  leaf  contains  an  alkaloid  called  cocaine, 
(pronounced  kork&-in)  now  largely  used  in  some  branches  of  surgery. 

Quinine , etc.,  The  bark  of  the  cinchonas,  espec- 

ially that  of  the  roots,  contains  many  alkaloids.  Some  are  crys- 
tallizable  and  some  are  not.  The  principal  crystallizable  ones  in 
the  bark  are  quinine  and  quinidine,  cinchonine  and  cinchonidine. 
The  bark  yields  approximately  as  follows,  the  amounts  varying 
with  the  kinds  of  bark  : 


Of  quinine, 

Of  quinidine, 

Of  cinchonine, 
Of  cinchonidine, 


.4  to  1 1.6  % ) 
.8  to  .9  % i 
.4  to  2.2  % ) 
.4  to  5.2  % ) 


^20^24^202- 


Q9H22N2O. 


The  trees  producing  quinine  vary  in  size.  Sometimes  they  are 
only  shrubs  of  8 or  10  feet  ; in  other  cases  tall  trees. 

The  alkaloid,  quinine,  is  of  great  value  in  medicine,  having  re- 
markable specific  power  in  the  cure  of  intermittent  fevers.  The 
use  of  the  bark  itself  in  medicine  is  now  very  much  diminished. 
The  alkaloids  are  extracted  in  a state  of  greater  or  less  purity, 
the  one  chiefly  used  being  quinine,  and  this  in  the  form  of  a white 
salt,  a sulphate,  often  called  sulphate  of  quinia. 

Artificial  preparation  of  quinine  suggested.  It  has  long  been  known  that 
quinine  under  some  chemical  conditions  is  decomposed  into  several  substances, 
one  of  which  is  quinoline  (C9H7N).  Now  quinoline  is  found  in  certain  coal-tar 
products.  It  has  also  been  produced  by  Skraup  from  a mixture  of  aniline, 
nitro-benzene  and  glycerin.  The  suggestion  has  naturally  arisen  that  if  quinine 
can  be  broken  down  into  quinoline,  perhaps  quinoline  can  be  artificially  built 
up  into  quinine.  This  idea  receives  encouragement  from  the  fact  that  alizarin 
has  been  produced  artificially  from  anthracene.  Moreover  the  great  importance 
and  value  of  quinine  and  the  expense  of  obtaining  it  from  bark,  offer  a strong 
stimulus  to  investigation  looking  toward  its  artificial  preparation. 

Preparation  of  quinine. — There  are  many  ways  of  extracting  quinine  from 
the  bark.  They  all  involve  three  general  principles  : First,  quinine  combines 
with  hydrochloric,  sulphuric  or  other  acids,  to  form  salts  ; second,  when  such 
salt  is  treated  with  lime  or  other  suitable  alkali,  the  acid  is  withdrawn  and  the 
quinine  is  liberated  in  a form  insoluble  in  water;  third,  the  liberated  quinine  is 
removed  by  solution  in  some  suitable  solvent,  such  as  ether,  alcohol,  chloro- 
form, or  other  liquid  of  similar  general  character. 


Morphine , C17H19N03 

Codeine  ( methyl  morphine ),  C18H2iN03 
Narcotine , C22H23N07 


These,  and  many  others, 
are  derived  from  opium. 


ALKALOIDS . 


183- 


Opium  as  it  appears  in  commerce  is  a hardened  mass  of  juice 
from  unripe  capsules  of  the  poppy.  The  supply  of  the  world  is 
derived  from  Asia  Minor,  Persia,  India,  China  and  Egypt.  China 
is  said  to  consume  the  larger  proportion  of  the  total  amount  of  the 
opium  produced. 

Various  kinds  of  opium  vary  very  much  in  quality.  An  aver- 
age statement  of  the  alkaloids  is  as  follows  : 

Morphine,  . . . . . 6.  to  15.  % 

Narcotine,  . . . . . 4.  to  8.  % 

Other  alkaloids,  . . . . 5.  to  2.  % 

Opium  and  its  preparations  are  among  the  most  important  rem- 
edial agents  known.  Their  most  valuable  constituent  is  mor- 
phine, a white  crystallizable  substance  having  a bitter  taste.  Like 
other  alkaloids  it  is  capable  of  combination  with  acids  to  form 
salts. 

In  general,  to  prepare  morphine,  the  opium  is  treated  as  fol- 
lows : It  is  macerated  with  water  ; the  water  extract  is  filtered 
and  then  evaporated  ; from  the  evaporated  residue  the  pure  alka- 
loid is  extracted  by  use  of  a mixture  of  alcohol  and  ether;  this 
last  solution  is  evaporated,  to  yield  crystals  of  morphine. 

Atropine , C17H22N03.  It  occurs  in  atropa  belladonna , and  in 
datura  stramonium.  Applied  to  the  eye,  it  enlarges  the  pupil. 

Cocaine , C17H2iN04.  It  occurs  in  the  leaves  of  erythroxylon 
coca. 

Strychnine , C21H22N202  \ These  alkaloids  occur  in  nux  vomica, 

Brucine , C23H26N204  S in  St.  Ignatius’  bean  and  in  other 

vegetable  substances. 

Veratrine , C32H49N09.  It  occurs  in  veratrum  sabadilla>  and 
elsewhere. 

Aconitine , C33H43N012.  It  occurs  in  the  root  of  monkshood, 
aconitum  napellus . 

Solanine , C52H93N018(?).  It  occurs  in  the  berries  of  the  deadly 
nightshade,  solanum  nigrum , and  in  many  parts  of  different  sola- 
nums ; in  small  quantity  in  even  the  tubers  and  leaves  of  the 
edible  potato,  s.  tuberosum. 


INDEX 


Acetic  acid,  83 
Acetone,  104 
Acetylene,  36,  45 
Acids,  23,  80,  166 

amides,  133 

Aconitine,  183 
Agar,  129 
Alcohol,  23,  64,  164 
Aldehydes,  24,  102 
Alizarin,  150,  163,  178 
Alkaloids,  180 
Alkyl  radicles,  23 
Allylene,  45 
Aluminium  acetate,  S6 
Amido-acids,  133 

benzene,  160 

Amines,  24,  131 
Anthracene,  150 
Aniline,  160 

black, 175 

Anthramine,  161 
Anthraquinone,  162 
Arabin,  129 
Argol,  99 

Aromatic  amines,  159 

compounds,  27,  136 

hydrocarbons,  143, 

1 45  . 

derivatives,  158 

Asphaltum,  61 
Atropine,  183 
Azo-compounds,  161, 

172.  173 
Balata,  157 
Beer,  70 

Benzene,  27,  136,  146 
Benzine,  27 
Benzoic  acid,  167 
Brazilin,  179 
Brazilwood,  179 
Brucine,  1S3 
Butane,  43 
Butter,  93 
Butyric  acid,  87 
Caffeine,  181 
Camphor,  153 
Cane  sugar,  110 
Caoutchouc,  154 
Capric  acid,  88 
Caproic  acid,  88  ' 

Caprylic  acid,  88 
Carbohydrates,  105 
Carbon  disulphide,  29 
Carbonic  acid,  95 
Carminic  acid,  179 
Cellular  substances,  2 
Celluloid,  124 
Cellulose,  105,  122 
Chloral,  103 
Chloroform,  63 
Chromogenes,  171 
Chromphores,  171 
Cinchonine,  182 
Citric  acid,  100 
Coal  tar,  146 
Coal  tar  colors,  170 
Coca,  182 
Cocoa,  1 81 


Cochineal,  179 
Codeine,  182 
Coloring  matters,  170 
Coniine,  181 
Corn  oil,  1 19 
Cream  of  tartar,  100 
Cresol,  166 
Cotton,  128 
Cotton  seed  oil,  91 
Cumene,  14S 
Curarine,  181 
Cyanogen,  29,  32, 134 
Cymene,  148 
Diacetylene,  147 
Diamines,  133 
Diazocompounds,  161 
Dulcite,  75 
Durene,  148 
Dynamite,  75 
Ethane,  42 
Ethers,  23,  76,  163 
Ethylamine,  133 
Ethylene,  36,  45 
Ethyl  alcohol,  68 

ether,  77 

Ester,  76,  78 
Kats,  89 
Fatty  acids,  80 

compounds,  27,  34, 

3S 

Fehling’s  solution,  106 
Ferments,  68 
Formalin,  102 
Formic  acid,  82 
Fractional  distillation, 
20 

Fructose,  109 
Fuchsine,  174 
Fumaric  acid,  98 
Fulminic  acid,  33 
Fustic  178 
Gallic  acid,  167 
Glucose,  10S 
Glucosides,  129 
Glycerin,  72 
Glycol,  72 
Glycollic  acid,  96 
Gums,  129 
Gun  cotton,  124 
Guttapercha,  157 
Haematoxylin,  179 
Halogen  derivatives, 
62, 15S 

Heptose,  108 
Heterologous  com- 
pounds, 36 
Hexane,  43 
Hexose,  108 
Homologous  series,  36 
Hydrazines,  133 
Hydrocarbons, 23, 35, 38 
Indigotin,  177 
Ink,  16S 

India  rubber,  154 
Iron  acetate,  87 
Isocetic  acid,  8S 
Isomerism,  5,  40 
Isoprene, 46 


Kekule’s  ring,  138 
Ketones,  24,  102 
Lactic  acid,  96 
Lactose,  no 
Laevulose,  109 
Laurie  acid,  88 
Lead  acetate,  S6 
Linoleic  acid,  95 
Logwood,  179 
Madder,  163,  178 
Maleic  acid,  9S 
Malic  acid,  98 
Malonic  acid,  97 
Maltose,  no 
Mannite,  75 
Margaric  acid,  89 
Mellitene,  148 
Mellitic  acid,  167 
Mesitylene,  148 
Mercuric  cyanide,  31 
Mecuric  sulpho- 
cyanate,  33. 

Metals  in  organic 
compounds,  135 
Metamerism,  5,  6 
Methane,  42 
Methyl  alcohol,  66 

amine,  133 

chloride,  62 

ether,  77 

Methylated  spirits,  67 
Milk  sugar,  no 
Molecular  structure,  7 
Mordants,  86 
Moritannic  acid,  178 
Morphine,  182 
Myristic  acid,  88 
Naphthalene,  149 
Naphthol,  166 
Naphthylamine,  161 
Natural  gas,  60 
Nicotine,  181 
Nitriles,  134 
Nitrobenzene,  15S 
Nitro-compounds,  26 
Nitroglycerin,  73 
Nitronaphthalene,  159 
Nitrotoluene,  159 
Oenanthylic  acid,  SS 
Oils,  89 
Olefines,  44 
Oleic  acid,  95 
Olein,  95 

Oleomargarine,  93 
Opium,  183 
Orientation  in  ben- 
zene ring,  140 
Ortho  compounds,  r4i 
Oxalic  acid,  97 
Ozocerite,  61 
Palmitic  acid,  89 
Paper,  125 

Para  compounds,  141 
Paraffins,  38 
Pelargonic  acid,  88 
Pentane,  43 
Peruvian  bark,  182 


Petroleum,  48 
Pharoah’s  serpents,  33 
Phenol,  164 
Phenolphthalein,  175 
Phenylamine,  160 
Phenyl  hydrazine,  107 
Picric  acid,  165 
Pitch,  153 

Potassium  cyanate,  32 

cyanide,  30 

ferricyanide,  30 

ferrocyanide,  30 

sulphocyanate,  33 

Propane,  43 
Propionic  acid,  87 
Pyridine,  180 
Pyrogallol,  165 
Pyroxyline,  124 
Quercitron,  179 
Quinine,  182 
Quinone,  162 
Racemic  acid,  98 
Rational  formulas,  6 
Radicles,  4,  22 
Red  liquor,  86 
Ricinoleic  acid,  96 
Rosaniline,  172,  175 
Rosin,  153 
Saccharine,  169 
Salicylic  acid,  167 
Santalin,  179 
Saturated  compounds,  7 
Silicon  compounds,  9 
Soap, 93 
Solanine,  183 
Sorghum,  116 
Sparteine,  181 
Starch,  105,  119 
Stearic  acid,  S9 
Stearin,  93 
Strychnine,  183 
Succinic  acid,  97 
Sugar,  106,  1 17 
Sulphur  compounds, 
29.  79 

Sulphonic  acids,  25 
Sulphocyanic  acid,  33 
Tannic  acid,  168 
Tar,  153 

Tartar  emetic,  100 
Tartaric  acid,  9S 
Theine,  181 
Theobromine,  1S1 
Thiocyanic  acid,  33 
Toluene,  147 
Toluidine,  161 
Triphenylmethane 
compounds,  173 
Turpentine,  151 
Unsaturated  com- 
pounds, 7 
Urea.  32 
Valeric  acid,  88 
Valylene,  36,  46 
Veratrine,  183 
Wine,  70 
Xylene,  148 


